Skip to main content

2017 | Book

Musical Instruments in the 21st Century

Identities, Configurations, Practices

Editors: Till Bovermann, Alberto de Campo, Hauke Egermann, Sarah-Indriyati Hardjowirogo, Stefan Weinzierl

Publisher: Springer Singapore


About this book

By exploring the many different types and forms of contemporary musical instruments, this book contributes to a better understanding of the conditions of instrumentality in the 21st century. Providing insights from science, humanities and the arts, authors from a wide range of disciplines discuss the following questions:

· What are the conditions under which an object is recognized as a musical instrument?

· What are the actions and procedures typically associated with musical instruments?

· What kind of (mental and physical) knowledge do we access in order to recognize or use something as a musical instrument?

· How is this knowledge being shaped by cultural conventions and temporal conditions?

· How do algorithmic processes 'change the game' of musical performance, and as a result, how do they affect notions of instrumentality?

· How do we address the question of instrumental identity within an instrument's design process?

· What properties can be used to differentiate successful and unsuccessful instruments? Do these properties also contribute to the instrumentality of an object in general? What does success mean within an artistic, commercial, technological, or scientific context?

Table of Contents

This book started as a number of notes attached to a wall, with eight people from different academic backgrounds sticking little dots on them. The notes had several keywords written on them, “electronic music”, “live performance”, “improvisation” and the like. The points were used to vote for a keyword that would set the thematic focus of an upcoming workshop, which was meant to prepare the ground for the work on this book. There was a lively debate on which keyword represented the most promising topic in the context of contemporary musical instruments that would be of interest not only to scholars from diverse academic fields, but also to practitioners both from musical instrument design and artistic practice. Eventually, the winning note was the one that read “instrumentality”. There had been a lot of discussion around that term beforehand, and it seemed to offer an interesting anchor for a book that was intended to juxtapose a variety of perspectives related to contemporary musical instruments.
Till Bovermann, Alberto de Campo, Hauke Egermann, Sarah Hardjowirogo, Stefan Weinzierl

Think Know Reflect

Instrumentality. On the Construction of Instrumental Identity
The musical instruments of the 21st century and those of earlier times differ in many respects, be it their appearance, their technical functionality, their playing technique, or their sounds. And as they have changed, so too have our understandings of what a musical instrument is. The lacking precision of the current notion of the instrument and its incompatibility with contemporary instrumental forms are consequences of a technocultural process that raises fundamental questions about the identity of the musical instrument: When (and why) is something a musical instrument—and when (and why) is it not? In order to grasp the slight differences between the yet-to-be-defined instrumental and the assumed other, it seems reasonable to speak of instrumentality when denoting this particular specificity that instruments are supposed to feature. The present contribution seeks to prepare the ground for a reflective discussion on the concept of instrumentality and the underlying theoretical problem by considering not only the differences, but also the similarities between traditional and electronic musical instruments. Using a couple of different approaches to and views on the concept and defining a number of criteria of instrumentality, it eventually yields a picture of musical instruments that connects the contemporary ones with those known for centuries.
Sarah-Indriyati Hardjowirogo
From Musical Instruments as Ontological Entities to Instrumental Quality: A Linguistic Exploration of Musical Instrumentality in the Digital Era
The development of electricity, sound technology, electronics and computer science during the last 150 years has allowed the emergence of new kinds of musical devices. This paradigm shift from traditional to digital instruments has strong consequences for instrument identity and for the relationship between the musician and her/his instrument. Grounded in a situated cognitive linguistics perspective, this contribution first explores various definitions of the instrument (from general dictionaries and musicology literature) before analysing how members of the computer music community name and define their instrument/interface/device, etc. Analysing the different strategies of instrument naming used by designers and users of digital instruments and by authors in computer music literature allows us to study the on-going construction and negotiation of a new terminology. By highlighting the instability, the fuzziness but also the diversity of what an instrument is to these different speakers, these analyses contribute to a better understanding of the conditions of instrumentality in the digital era. More than just referring to a device, the notion of instrument rather qualifies the interaction with the users, thus allowing a new shift from the instrument as an ontological entity to an instrumental quality.
Caroline Cance
From Idiophone to Touchpad. The Technological Development to the Virtual Musical Instrument
The history of music can be understood as the increasing digitalization of representation and processing of musical information as notes and sounds. Musical phenomena could be described as a continuous transition from the analog and simple instrument like a wood block to the digital and abstract software instrument like a virtual synthesizer on a touchpad. The development of musical instruments shows an increase in complexity and functionality of handicraft over time, and the music computer forms the last, most comprehensive and most abstract link in a chain of innumerable steps in music and musical technology, starting with the human voice and the invention of drums as a mean of sound and communication and actually marked by digital instruments and virtual sound worlds. Ten developmental stages can be identified with regard to the construction and the usage of musical instruments and multimedia performances. The digital processing of sound information extends the range of artistic presentation of musical processes to unfamiliar, albeit intriguing and expandable dimensions. The aesthetic potential of the artistic approach to musical and multimedia information in the broadest sense proves to be enormous. But it is impossible to predict whether overarching paradigms of music composing and digital culture will emerge or become apparent some day.
Bernd Enders
Musical Instruments as Assemblage
Traditional analysis and classification of musical instruments is often based on an account of the material characteristics of instruments as physical objects. In this sense, their material basis as a kind of purpose-built technology is the primary focus of concern. This chapter takes the position that musical instruments are better understood in terms of their place in a network of relationships—an “assemblage”—with other objects, practices, institutions and social discourses. Particular attention is applied to the violin, the electric guitar and the phonographic turntable as examples. The assemblage is variable, and the same instrument can be used differently and take on different meanings depending on its place within a particular assemblage; indeed, it is the assemblage that allows us to consider devices like turntables as musical instruments even though they were not designed for such purposes.
Paul Théberge
Instrumentality as Distributed, Interpersonal, and Self-Agential: Aesthetic Implications of an Instrumental Assemblage and Its Fortuitous Voice
Philip Alperson, in ‘The Instrumentality of Music’, extends the commonsense concept of musical instrument to an understanding encompassing the instrument’s musical, cultural and conceptual situation. This understanding shifts the focus from a work-based aesthetic to one in which “listeners appreciate the human achievement with specific regard to accomplishment in the context of the demands of the particular instrument involved”. With this advanced understanding of instruments and the instrumentality of music in place, I shall discuss a moment of genuine instrumental discovery (as opposed to deliberate design). During an improvisatory extension of the piano’s sound board as part of a trio exploration with Bennett Hogg and Sabine Vogel using fishing wire, suspended bansuri flutes, contact microphones, and, vitally, transducers placed inside violins and on the piano’s sound board, an unintended feedback loop formed, resulting in an additional voice, curiously turning the trio into a quartet. While the found voice’s dynamics and character could be nuanced by varying the dampening of singular piano strings, as well as via the sustain pedal, it could, overall, only be summoned up and influenced in an indirect manner, via an ensemble effort. In analysing the situation of the discovery and in discussing its aesthetic implications, I offer a contribution to Alperson’s notion of instrumentality in two respects: performers may together form a single voice, that is, their instrumentality might join; and an installation may, under certain conditions, acquire its own instrumental agency and identity, extending the cultural situation to include the natural environment, and the algorithmic.
Deniz Peters
Interactivity of Digital Musical Instruments: Implications of Classifying Musical Instruments on Basic Music Research
The introduction of the computer as musical instrument and the development of interactive musical instruments have led to completely new purposes and questions for music research; as a result, it no longer seems adequate to rely on the traditional classification of musical instruments, which is based on the purpose of instrument design and presentation of instruments in public or private exhibition. Based on insights from the philosophy of science, this paper suggests pursuing another purpose of and approach to instrument classification appropriate for basic music research. We argue that (digital) computing systems, to some extent, have the potential to act as autonomous and artificial social agents. This argument is based on the conceptualization of machines as (abstract) automata. In addition, we exploit concepts from dynamic systems theory in a metaphorical manner to find a more appropriate point of view to develop new research questions. Discussing interactivity, for which embodiment and situatedness are prerequisites, we suggest taking interactivity, agency, and autonomy into account to develop an appropriate classification system of musical instruments and at the same time to rethink the traditional concept of musical instrument. Whether a musical instrument can be defined as broader than a device that has the function of generating sounds, i.e. whether it can be viewed as an embodied, situated or even social agent, remains a challenging question for basic music research. To discuss this question, not only sound generating actions, but also other musically meaningful actions that involve agency should be taken for granted.
Jin Hyun Kim, Uwe Seifert

Design Make Create

Movement Meets Material—An Improvisational Approach to Design
How can we integrate an embodied musician-instrument relation to musical instrument design? To answer this question, we have proposed a design process where musical instrument prototypes are developed taking a specific improvisation practice from contemporary dance. Over the course of four improvisation sessions, we invited an acoustic musician, an experimental electronic musician and a contemporary dancer to develop a solo performance with given material. Their improvisations inspired the design of three instrument mock-ups, which integrated movement, material and sound. After four subsequent improvisation sessions the process resulted in two refined instrument prototypes. Using improvisation as a performance setting, our developmental process revealed that for live set-ups the instrument benefits from a reliable system, which allows the musician to perform in a spontaneous and flexible manner. To further engage the musician with the instrument, the sound synthesis process should reflect genuine material sound qualities of the object. Emphasizing its identity as an instrument, we refer to this as material authenticity, a notion, which raises questions on the relationship between material, digitality and sound.
Johanna Schindler, Amelie Hinrichsen
Instrumentality, Time and Perseverance
In this article we discuss how the act of perceiving a digital object as a musical instrument can be considered as directly proportional to the amount (and quality) of time invested in its development and refinement to suit individual needs rather than generic ones. In that regard, the purpose-free approach to the design of generic controllers contrasts with a view of personalised tools developed and continuously redefined by the artist to fulfil artistic and musical needs. In doing so, the time invested relates to the artist/designer’s perseverance in a never-ending process of subjectification of the digital instrument identity. The discussion provided in the article is supported by a case study on one of the pioneers and developers of digital musical instruments: Michael Waisvisz (1949–2008) and his work on The Hands (first exhibited in 1984—last performance dated 2008). We argue that this almost 30-year long and engaged process of development and experimentation can be seen as a model, through which we can allow other musical devices to evolve from controllers of digital musical matter to instruments that may provide integrated and embodied possibilities for musical expression.
Giuseppe Torre, Kristina Andersen
Machine Learning as Meta-Instrument: Human-Machine Partnerships Shaping Expressive Instrumental Creation
In this chapter, I describe how supervised learning algorithms can be used to build new digital musical instruments. Rather than merely serving as methods for inferring mathematical relationships from data, I show how these algorithms can be understood as valuable design tools that support embodied, real-time, creative practices. Through this discussion, I argue that the relationship between instrument builders and instrument creation tools warrants closer consideration: the affordances of a creation tool shape the musical potential of the instruments that are built, as well as the experiences and even the creative aims of the human builder. Understanding creation tools as “instruments” themselves invites us to examine them from perspectives informed by past work on performer-instrument interactions.
Rebecca Fiebrink
Interfacing Sound: Visual Representation of Sound in Musical Software Instruments
This chapter explores the role of visual representation of sound in music software. Software design often remediates older technologies, such as common music notation, the analogue tape, outboard studio equipment, as well as applying metaphors from acoustic and electric instruments. In that context, the aim here will be study particular modes in which abstract shapes, symbols and innovative notations can be applied in systems for composition and live performance. Considering the practically infinite possibilities of representation of sound in digital systems—both in terms of visual display and mapping of gestural controllers to sound—the concepts of graphic design, notation and performance will be discussed in relation to four systems created by the author: ixi software, ixiQuarks, ixi lang, and the Threnoscope live coding environment. These will be presented as examples of limited systems that frame the musician’s compositional thoughts providing a constrained palette of musical possibilities. What this software has in common is the integral use of visual elements in musical composition, equally as prescriptive and representative notation for musical processes. The chapter will present the development of musical software as a form of composition: it is an experimental activity that goes hand in hand with sound and music research, where the musician-programmer has to gain a formal understanding of diverse domains that before might have been tacit knowledge. The digital system’s requirements for abstractions of the source domain, specifications of material, and completeness of definitions are all features that inevitably require a very strong understanding of the source domain.
Thor Magnusson
Digital Media and Electronic Music in the Classroom—The Loop Ensemble
The production, performance, storing, processing, dissemination and reproduction of music are and always have been technologically determined. The continuing digitalization benefits and accelerates this development. At present, children and adolescents grow up in this cultural environment, their perception and handling of music is pervaded by digital technology. But despite their cultural relevance and several impulses from the academical discourse, these aspects of music culture are still marginalized in the educational practice in German classrooms. Younger research focuses the adequacy of music software for educational purposes, formulating the need of educationally suited software. Research shows, that main obstacles with integrating digital music media into education are the high cost and the deterrent complexity of music software. In the context of the interdisciplinary research project 3DMIN, we developed the loop ensemble. It consists of three virtual instruments created in the open source software Pure Data and is designed for the practical dissemination of electronic music culture and its technical basics in a pedagogical context. As an Open Educational Resource it is designed as didactic material for an action-oriented music education in combination with autonomous learning. We evaluated the instruments’ usability in three ways. The results show a distinct practical suitability of the ensemble, yet further empirical research is needed for a profound evaluation.
Marten Seedorf, Christof Martin Schultz
The Birl: Adventures in the Development of an Electronic Wind Instrument
This article reflects on the markedly distinct development stages of an electronic wind instrument called the Birl. Stemming from an early idea for an electro-mechanical oscillator inspired by the sounds of pen plotters, the Birl was formed through the connection of that oscillator prototype to a rough wind instrument body. Originally intended to fulfill the role of the wind section in an ensemble of instruments built for the author’s doctoral dissertation composition, the instrument took on a new life after the completion of the piece. The development of a “cello-like” resonator body and refinements to the electro-mechanical aspects had brought the instrument to a performable state, but several limitations suggested further development. A desire to make the instrument more conducive to exploratory improvisation pushed the Birl in new directions, toward open-holed fingering systems and embouchure sensors with neural net mapping structures and physical models of dynamically configurable toneholes, resulting in an instrument that bore little resemblance to the original electro-mechanical concept. The author discusses the design challenges that arose as the instrument evolved, the solutions that were found along the way, and the ways in which user feedback informed the design as the needs of the instrument changed.
Jeff Snyder
Case Study: The Endangered Guitar
The author describes his 15-year development of the hybrid interactive instrument “Endangered Guitar”, and how it grew out of an already decade long practice of sonic performances on guitar, followed his aesthetic interests through hundreds of concerts, and influenced these interests in turn. The Endangered Guitar is an instrument is made to facilitate live sound processing. The software “listens” to the guitar input, to then determine the parameters of the electronic processing of the same sounds, responding in a flexible way. The instrument is interactive, in that it does not react in a fully predictable way to the input of the performer. The author makes a case that in order to truly improvise with electronics one has to program “uncertainties” into the machine. He uses weighted random functions, feedback strategies, and the fuzzy behavior of pitch tracking devices when presented with overtone-rich sounds, which the performer draws from the guitar with a variety of tools.
Hans Tammen

Compose Play Perform

Interplay Between Composition, Instrument Design and Performance
With electronics and code as an essential part of new musical instruments, the boundaries between composition, instrument design and performance are blurring. With code that can be changed and compiled on the fly, the design of an instrument becomes a fluid process, which can even be a performance in itself. Starting with an example from my own artistic practice, I explore the concepts of composition, instrument and performance and what role the design of electronics and software plays in these. What influences design decisions when developing instrument? How does the materiality of electronics and code inform these decisions? How do the knowledge and skills of the makers play their role in this?
M. A. J. Baalman
Instrumentality in Sonic Wild{er}ness
In 2015, a group of six sound practitioners including the authors came together for ‘Sonic Wild Code’ and engaged in a series of sonic wilderness interventions with portable electronic instruments. We investigated notions of coexistence, communication and potential for interaction in the hybrid ecology surrounding the lake and settlement of Kilpisjärvi, located close to the three-nation corner of Finland, Sweden and Norway. By immersing ourselves into the vast and raw landscape of the Samiland, we researched and tested musical conversations between us players and the site which we found sounding, vibrating, and speaking for itself. This text is a collection of fragments originating in discussions between the two authors on the theme of such sonic wilderness interventions.
Antye Greie-Ripatti, Till Bovermann
Instrumental Modality. On Wanting to Play Something
Composer/Performer Jeff Carey and Performer/Composer Bjørnar Habbestad have collaborated since 2002, developing a chain of works, performances and improvised events as the duo USA/USB. Parallel to their artistic work runs a development effort in SuperCollider, now branched into what is known as Modality (http://​modality.​bek.​no)—a network of developers collaborating on the creation of a toolkit to support live electronic performance environments. In this interview Habbestad and Carey share insights to this development process whilst discussing what it means to play an instrument in a computer music context.
Bjørnar Habbestad, Jeff Carey
Instruments for Spatial Sound Control in Real Time Music Performances. A Review
The systematic arrangement of sound in space is widely considered as one important compositional design category of Western art music and acoustic media art in the 20th century. A lot of attention has been paid to the artistic concepts of sound in space and its reproduction through loudspeaker systems. Much less attention has been attracted by live-interactive practices and tools for spatialisation as performance practice. As a contribution to this topic, the current study has conducted an inventory of controllers for the real time spatialisation of sound as part of musical performances, and classified them both along different interface paradigms and according to their scope of spatial control. By means of a literature study, we were able to identify 31 different spatialisation interfaces presented to the public in context of artistic performances or at relevant conferences on the subject. Considering that only a small proportion of these interfaces combines spatialisation and sound production, it seems that in most cases the projection of sound in space is not delegated to a musical performer but regarded as a compositional problem or as a separate performative dimension. With the exception of the mixing desk and its fader board paradigm as used for the performance of acousmatic music with loudspeaker orchestras, all devices are individual design solutions developed for a specific artistic context. We conclude that, if controllers for sound spatialisation were supposed to be perceived as musical instruments in a narrow sense, meeting certain aspects of instrumentality, immediacy, liveness, and learnability, new design strategies would be required.
Andreas Pysiewicz, Stefan Weinzierl
Lucille Meets GuitarBot: Instrumentality, Agency, and Technology in Musical Performance
The relationship between musicians and their instruments in performance has been characterized in a variety of ways that tend to describe the instrument either as an entity inseparable from the musician or as an entity with relative autonomy. Through the trope of ventriloquism, Philip Auslander looks at how two musicians working in very different genre contexts construct their respective relationships to instruments in performance. Both blues guitarist and singer B.B. King and classical violinist Mari Kimura treat instruments as entities separate from themselves and performers in their own right: King by naming his guitar Lucille and constructing a narrative around his relationship with her, and Kimura through her interaction with GuitarBot, a digital musical instrument. By dramatizing the ventriloquial relationship between player and instrument and creating the impression that an instrument possesses an identity and agency, both King and Kimura enact the fantasy of instrumental autonomy that underlies the ventriloquial relationship between performer and instrument. But because the digital technology Kimura employs allows GuitarBot a greater degree of (apparent) autonomy than Lucille, who is always under King’s visible, physical control, it enables her to push the enactment of this fantasy further toward the uncanny to show us what it might look like for a performer to interact with a genuinely autonomous musical instrument.
Philip Auslander
No Flute Is an Island, Entire of Itself. Transgressing Performers, Instruments and Instrumentality in Contemporary Music
What does an instrument offer us, and how does playing it, change this? Oscillating between personal experiences and select theoretical positions, the author discusses relationships between instrument and performer. Through a questioning of the validity of subject/object positions, the dilemma of instrumentality is introduced and the relevance of transgression used as an entry to a rethinking of instrumentality.
Bjørnar Habbestad
LiveCodeNet Ensamble: A Network for Improvising Music with Code
LiveCodeNet Ensamble is a laptop band from Mexico City that approaches computer music improvisation through live coding and a local network. This text discusses aspects of the ensemble's practice related to some elements of the SuperCollider program such as broadcast and history, and the concepts synchrony and collective listening in order to reflect on a collective instrument, group practice, and improvisation in the context of network music and live coding.
Hernani Villaseñor Ramírez
Three Flavors of Post-Instrumentalities: The Musical Practices of, and a Many-Festo by Trio Brachiale
This article offers a shared account of one out of a pluriverse of possible musics in the 21st century, with three personal perspectives. It is written by a trio of musicians/artists/researchers, who have been co-inventing an idiosyncratic style of music, including its instruments, compositional strategies, and performance systems. We articulate our artistic aims in a many-festo, discuss the background that informs our thinking, give examples of related artistic instrument design, and explain aspects of our own work that exemplify our essential insights and resulting tenets.
Dominik Hildebrand Marques Lopes, Hannes Hoelzl, Alberto de Campo

Listen Perceive Feel

Mapping, Causality and the Perception of Instrumentality: Theoretical and Empirical Approaches to the Audience’s Experience of Digital Musical Instruments
Digital musical instruments (DMIs) rarely feature a clear, causal relationship between the performer’s actions and the sounds produced. Instead, they often function simply as controllers, triggering sounds that are or have been synthesised elsewhere; they are not necessarily sources of sound in themselves (Miranda and Wanderley 2006). Consequently, the performer’s physical interaction with the device frequently does not appear to correlate directly with the sonic output, thus making it difficult for spectators to discern how gestures and actions are translated into sounds. This relationship between input and output is determined by the mapping, the term for the process of establishing relationships of cause and effect between the control and sound generation elements of the instrument (Hunt et al. 2003). While there has been much consideration of the creative and expressive potential of mapping from the perspective of the performer and/or instrument designer, there has been little focus on the experience of those receiving DMIs. How do spectators respond to the perceptual challenge DMIs present them? What influence do mapping and other aspects of instrument design (e.g. the type of controller used and the sound design) have on the success of an instrument when considered from the spectator’s point of view? And to what extent can (and should) this area of artistic exploration be made more accessible to audiences? This article aims to consider these questions through providing a critical review of the existing theoretical and empirical work on DMI reception.
Gina Emerson, Hauke Egermann
Western Orchestral Instruments in the Foreground: What Features Make an Instrument More Attractive for a Solo Role in Concertos?
Music often consists of multiple instruments and parts. Some serve a more foreground role (such as carrying a melody) whereas others offer background support (namely, as accompaniment). Musical solos are probably the clearest example of the foreground usage. What factors then make a specific instrument attractive for performing a solo? For example, an instrument might be preferred for a solo function if there are many virtuoso musicians. Or listeners might request a solo of a rare instrument. In this chapter, we examine the popularity of an instrument to play a solo role using four factors: pitch, loudness, timbre, and performer pool size. We focus on the concerto repertoire in Western classical music, since the titles bear a clear designation of the solo instrument(s). Our hypothesis is that an instrument will be attractive for a solo if it can produce high pitches and loud sounds, has a salient timbre, and has many skilled performers available to play it. Correlation and multiple regression results were mostly in agreement with the hypothesis; an instrument is more likely to serve in a solo role when it has a higher median pitch, a highly salient timbre, and there are a larger number of trained musicians.
Song Hui Chon
Instruments Unheard of: On the Role of Familiarity and Sound Source Categories in Timbre Perception
Musical timbre has traditionally been treated as a sensory phenomenon, that is, as a “surface feature” that resides in the musical moment. The role of familiarity with sound source categories and instrument families has remained unexplored. The current chapter takes a dedicatedly cognitive view on timbre and argues that long-term familiarity and knowledge about instrument categories affect even such supposedly low-level tasks as dissimilarity ratings. As a background, the chapter provides a conceptual framework for the notion of timbre, as well as an outline of basic results from timbre dissimilarity ratings and instrument identification. Results from a previous study on the role of sound source categories in timbre dissimilarity ratings are then discussed in depth (Siedenburg et al. in Frontiers in Psychology 6, 2016b). This study collected timbre dissimilarity ratings for tones from acoustic musical instruments as well as for novel, digitally transformed tones. The main pieces of evidence to be discussed come from rating asymmetries and a regression model. It is argued that timbre perception is characterized by an interplay of sensory and categorical representations, reflecting acoustic facets and learned sound source and instrument categories of musical instruments. Implications for the design of novel digital musical instrument design are being discussed.
Kai Siedenburg
What If Your Instrument Is Invisible?
As an electronic musician I am largely occupied with capturing and manipulation of sound in real time—specifically the sound of instruments being played by other musicians. Also being a singer, I’ve found that both of my instruments are often perceived as “invisible”. This article discusses various strategies I developed, over a number of years, in order to “play” sound manipulations in musically reactive ways, to create a live sound-processing “instrument”. Problems were encountered in explaining what I do to other musicians, audience, and audio engineers about what I do, technically and musically. These difficulties caused me to develop specific ways to address the aesthetic issues of live sound-processing, and to better incorporate my body into performance, both of which ultimately helped alleviate the invisibility problem and make better music.
Dafna Naphtali
Musical Instruments in the 21st Century
Till Bovermann
Alberto de Campo
Hauke Egermann
Sarah-Indriyati Hardjowirogo
Stefan Weinzierl
Copyright Year
Springer Singapore
Electronic ISBN
Print ISBN

Premium Partners