Carver Mead in 2002
May 1, 1934 |
|Thesis||Transistor Switching Analysis (1960)|
|Doctoral advisor||R. D. Middlebrook
Robert V. Langmuir
|Notable awards||National Medal of Technology
2011 BBVA Foundation Frontiers of Knowledge Award
Computer History Museum Fellow (2002)
|Carver Mead, Winner of 1999 Lemelson-MIT Prize], Lemelson Foundation|
|Carver Mead - Semiconductors, April 17, 2014, The Official ACM|
|Carver Mead presents The Universe and Us: An Integrated Theory of Electromagnetics and Gravitation, TTI/Vanguard|
Carver Andress Mead (born 1 May 1934) is a US scientist and engineer. He currently holds the position of Gordon and Betty Moore Professor Emeritus of Engineering and Applied Science at the California Institute of Technology (Caltech), having taught there for over 40 years. Mead is an enthusiastic instructor, and advised the first woman to become an electrical engineering student at Caltech, Louise Kirkbride. His contributions as a teacher include the classic textbook Introduction to VLSI Design (1980), which he coauthored with Lynn Conway.
A pioneer of modern microelectronics, he has made contributions to the development and design of semiconductors, digital chips, and silicon compilers, technologies which form the foundations of modern VLSI chip design. In the 1980s, he focused on electronic modelling of human neurology and biology, creating "neuromorphic electronic systems." Mead has been involved in the founding of more than 20 companies. Most recently, he has called for the reconceptualization of modern physics, revisiting the theoretical debates of Niels Bohr, Albert Einstein and others in light of later experiments and developments in instrumentation.
Early life and education
Carver Andress Mead was born in Bakersfield, California and grew up in Kernville, California. His father worked in a power plant at the Big Creek Hydroelectric Project, owned by Southern California Edison Company. Carver attended a tiny local school for some years, then moved to Fresno, California to live with his grandmother so that he could attend a larger high school. He became interested in electricity and electronics while very young, seeing the work at the power plant, experimenting with electrical equipment, qualifying for an amateur radio license and in high school working at local radio stations.
Mead's contributions have arisen from the application of basic physics to the development of electronic devices, often in novel ways. During the 1960s, he carried out systematic investigations into the energy behavior of electrons in insulators and semiconductors, developing a deep understanding of electron tunneling, barrier behavior and hot-electron transport. In 1960, he was the first person to describe and demonstrate a three-terminal solid-state device based on the operating principles of electron tunnelling and hot-electron transport. In 1962 he demonstrated that using tunnel emission, hot electrons retained energy when traveling nanometer distances in gold. His studies of III-V compounds (with W. G. Spitzer) established the importance of interface states, laying the groundwork for band-gap engineering and the development of heterojunction devices.
In 1966, Mead designed the first gallium arsenide gate field-effect transistor using a Schottky barrier diode to isolate the gate from the channel. As a material, GaAs offers much higher electron mobility and higher saturation velocity than silicon. The GaAs MESFET became the dominant microwave semiconductor device, used in a variety of high-frequency wireless electronics, including microwave communication systems in radio telescopes, satellite dishes and cellular phones. Carver's work on MESFETs also became the basis for the later development of HEMTs (High-electron-mobility transistors) by Fujitsu in 1980. HEMTs, like MESFETs, are accumulation-mode devices used in microwave receivers and telecommunication systems.
Mead is credited by Gordon Moore of coining the term Moore's law, to denote the prediction Moore made in 1965 about the growth rate of the component count, "a component being a transistor, resistor, diode or capacitor," fitting on a single integrated circuit. Moore and Mead began collaborating around 1959 when Moore gave Mead "cosmetic reject" transistors from Fairchild Semiconductor for his students to use in his classes. During the 1960s Mead made weekly visits to Fairchild, visiting the research and development labs and discussing their work with Moore. During one of their discussions, Moore asked Mead whether electron tunneling might limit the size of a workable transistor. When told that it would, he asked what the limit would be.
Stimulated by Moore's question, Mead and his students began a physics-based analysis of possible materials, trying to determine a lower bound for Moore's Law. In 1968, Mead demonstrated, contrary to common assumptions, that as transistors decreased in size, they would not become more fragile or hotter or more expensive or slower. Rather, he argued that transistors would get faster, better, cooler and cheaper as they were miniaturized. His results were initially met with considerable skepticism, but as designers experimented, more and more results supported his assertion. In 1972, Mead and graduate student Bruce Hoeneisen predicted that transistors could be made as small as 0.15 microns. This lower limit to transistor size was considerably smaller than had been generally expected. Despite initial doubts, Mead's prediction influenced the computer industry's development of submicron technology. When Mead's predicted target was achieved in actual transistor development in 2000, the transistor was highly similar to the one Mead had originally described.
Mead–Conway VLSI design
Mead was the first to predict the possibility of storing millions of transistors on a chip. His prediction implied that substantial changes in technology would have to occur to achieve such scalability. Mead was one of the first researchers to investigate techniques for very-large-scale integration, designing and creating high-complexity microchips.
He taught the world's first VLSI design course, at Caltech in 1970. Throughout the 1970s, with involvement and feedback from a succession of classes, Mead developed his ideas of integrated circuit and system design. He worked with Ivan Sutherland and Frederick B. Thompson to establish Computer Science as a department at Caltech, which formally occurred in 1976. Also in 1976, Mead co-authored a DARPA report with Ivan Sutherland and Thomas Eugene Everhart, assessing the limitations of current microelectronics fabrication and recommending research into the system design implications of "very-large-scale integrated circuits".
Beginning in 1975, Carver Mead collaborated with Lynn Conway from Xerox. They developed the landmark text Introduction to VLSI systems, published in 1979, an important spearhead of the Mead & Conway revolution. A pioneering textbook, it has been used in VLSI integrated circuit education all over the world for decades. The circulation of early preprint chapters in classes and among other researchers attracted widespread interest and and created a community of people interested in the approach. They also demonstrated the feasibility of multi-project shared-wafer methodology, creating chips for students in their classes.
Their work caused a paradigm shift, a "fundamental reassessment" of the development of integrated circuits, and "revolutionized the world of computers". In 1981, Mead and Conway received the Award for Achievement from Electronics Magazine in recognition of their contributions. More than 30 years later, the impact of their work is still being assessed.
Building on the ideas of VLSI design, Mead and his Ph.D. student David L. Johannsen created the first silicon compiler, capable of taking a user's specifications and automatically generating an integrated circuit. Mead, Johannsen, Edmund K. Cheng and others formed Silicon Compilers Inc. (SCI) in 1981. SCI designed one of the key chips for Digital Equipment Corporation’s MicroVAX minicomputer.
Mead and Conway laid the groundwork for the development of the MOSIS (Metal Oxide Semiconductor Implementation Service) and the fabrication of the first CMOS chip. Mead advocated for the idea of Fabless manufacturing in which customers specify their design needs to fabless semiconductor companies. The companies then design special-purpose chips and outsource the chip fabrication to less expensive overseas semiconductor foundries.
Neural models of computing
Next Carver Mead began to explore the potential for modelling biological systems of computation, both animal and human brains. His interest in biological models dated back at least to 1967, when he met biophysicist Max Delbrück. Delbrück had stimulated Mead's interest in transducer physiology, the transformations that occur between the physical input initiating a perceptual process and eventual perceptual phenomena.
Observing graded synaptic transmission in the retina, Mead became interested in the potential to treat transistors as analog devices rather than digital switches. He noted parallels between charges moving in MOS transistors operated in weak inversion and charges flowing across the membranes of neurons. He worked with Professor John Hopfield and Nobelist Richard Feynman, helping to create three new fields: Neural Networks, Neuromorphic Engineering, and the Physics of Computation. Mead, considered a founder of Neuromorphic Engineering, is credited with coining the term "neuromorphic processors".
Developing this new direction, Mead was successful in finding venture capital funding to support the start of a number of companies, in part due to an early connection with Arnold Beckman, chairman of the Caltech Board of Trustees. Mead has said that his preferred approach to development is "technology push", exploring something interesting and then developing useful applications for it.
In 1986, Mead and Federico Faggin founded Synaptics Inc. to develop analog circuits based in neural networking theories, suitable for use in vision and speech recognition. The first product that Synaptics brought to market was a pressure-sensitive computer touchpad, a form of sensing technology that rapidly replaced the trackball and mouse in laptop computers. The Synaptics touchpad was extremely successful, at one point capturing 70% of the touchpad market.
In 1988, Richard Francis Lyon and Carver Mead described the creation of an analog cochlea, modelling the fluid-dynamic traveling-wave system of the auditory portion of the inner ear. Lyon had previously described a computational model for the work of the cochlea. Such technology had potential applications in hearing aids, cochlear implants, and a variety of speech-recognition devices. Their work has inspired ongoing research, attempting to create a silicon analog that can emulate the signal processing capacities of a biological cochlea.
In 1991, Mead helped to form Sonix Technologies, Inc. (later Sonic Innovations Inc.), founded by Brigham Young University professors Doug Chabries and Richard Christiansen in Salt Lake City, Utah. Mead designed the computer chip for their hearing aids. In addition to being small, the chip was said to be the most powerful used in a hearing aid. Release of the company's first product, the Natura hearing aid, occurred in September 1998.
In the late 1980s, Mead advised Misha Mahowald, a PhD student in Computation and Neural Systems, to develop the silicon retina, using analog electrical circuits to mimic the biological functions of rod cells, cone cells, and other non-photoreceptive cells in the retina of the eye. Her 1992 thesis received Caltech's Milton and Francis Clauser Doctoral Prize for its originality and "potential for opening up new avenues of human thought and endeavor". As of 2001[update] her work was considered "the best attempt to date" to develop a stereoscopic vision system. Mead went on to describe an adaptive silicon retina, using a two-dimensional resistive network to model the first layer of visual processing in the outer plexiform layer of the retina.
Around 1999, Mead and others established Foveon, Inc. in Santa Clara, California to develop new digital camera technology based on neurally-inspired CMOS image sensor/processing chips. The image sensors in the Foveon X3 digital camera capture multiple colors for each pixel, detecting red, green and blue at different levels in the silicon sensor. This provides more complete information and better quality photos compared to standard cameras that detect one color per pixel. It has been hailed as revolutionary. In 2005, Carver Mead, Richard B. Merrill and Richard Francis Lyon of Foveon were awarded the Progress Medal of the Royal Photographic Society, for the development of the Foveon X3 sensor.
Mead's work underlies the development of computer processors whose electronic components are connected in ways that resemble biological synapses. In 1995 and 1996 Mead, Chris Diorio, and others presented single transistor silicon synapses capable of analog learning applications and long-term memory storage. Carver pioneered the use of floating-gate transistors as a means of non-volatile storage for neuromorphic and other analog circuits.
Mead and Diorio went on to found Impinj based on their work with floating-gate transistors. Using low-power methods of storing charges on floating-gate transistors, Impinj developed applications for flash memory storage and radio frequency identity tags (RFID).
Carver Mead has developed an approach he calls Collective Electrodynamics in which electromagnetic effects, including quantized energy transfer, are derived from the interactions of the wavefunctions of electrons behaving collectively. In this formulation, the photon is a non-entity, and Planck's energy–frequency relationship comes from the interactions of electron eigenstates. The approach is related to John Cramer's transactional interpretation of quantum mechanics, to the Wheeler–Feynman absorber theory of electrodynamics, and to Gilbert N. Lewis's early description of electromagnetic energy exchange at zero interval in spacetime.
Mead has been involved in the founding of at least 20 companies. The following list indicates some of the most significant, and their main contributions.
- Actel, field programmable gate arrays
- Foveon, silicon sensors for photographic imaging
- Impinj, self-adaptive microchips for flash memory and RFID
- Silicon Compilers, integrated circuit design
- Sonic Innovations, computer chips for hearing aids
- Synaptics, touch pads for computers
- 2011 BBVA Foundation Frontiers of Knowledge Award of Information and Communication Technologies "... for his influential thinking in silicon technology. His work has enabled the development of the microchips that drive the electronic devices (laptops, tablets, smartphones, DVD players) ubiquitous in our daily lives."
- 2002, National Medal of Technology
- 2002, Fellow of the Computer History Museum "for his contributions in pioneering the automation, methodology and teaching of integrated circuit design".
- 2001, Dickson Prize in Science, award announced 2001, lecture March 19, 2002
- 1999, Lemelson-MIT Prize
- 1997, Allen Newell Award, Association for Computing Machinery
- 1996, John Von Neumann Medal, Institute of Electrical and Electronics Engineers
- 1996, Phil Kaufman Award for his impact on electronic design industry
- 1992, Award for Outstanding Research, International Neural Network Society
- 1985, John Price Wetherill Medal from The Franklin Institute, with Lynn Conway
- 1985, Harry H. Goode Memorial Award, American Federation of Information Processing Societies
- 1984, Harold Pender Award, with Lynn Conway
- 1981, Award for Achievement from Electronics Magazine, with Lynn Conway
|Library resources about
|By Carver Mead|
- Brock, David C.; Thackray, Arnold (September 30, 2004). "Interview with Carver A. Mead". Center for Oral History. Philadelphia, Pennsylvania: Chemical Heritage Foundation.
- Mead, Carver A.; Cohen, Shirley K. (July 17, 1996). "Interview with Carver A. Mead (1934– )" (PDF). Oral History Project. Pasadena, California: California Institute of Technology Archives.
- "Carver Mead 2002 Fellow". Computer History Museum. Retrieved 4 June 2015.
- "The Life of a Caltech "Lifer"". Caltech. Caltech News and Events. Retrieved May 1, 2014.
- "Carver Mead to receive ACM Allen Newell Award". ACM Pressroom. September 30, 1997. Retrieved 5 June 2015.
- Marcus, Gary (November 20, 2012). "The Brain in the Machine". The New Yorker. Retrieved 8 June 2015.
- "National Medal of Technology awardedby President Bush to Caltech's Carver Mead". Calrech News and Events. October 22, 2003.
- "Carver Mead". American Spectator 34 (7): 68. 2001. Retrieved 8 June 2015.
- Brock, David C.; Thackray, Arnold (September 30, 2004). "Interview with Carver A. Mead". Center for Oral History. Chemical Heritage Foundation.
- "Carver Mead". Computation & Neural Systems. California Institute of Technology. Retrieved 4 June 2015.
- Mead, Carver A.; Cohen, Shirley K. (July 17, 1996). Interview with Carver A. Mead (1934– ) (PDF). Pasadena, California: Oral History Project, California Institute of Technology Archives.
- Mead, Carver A. "Brief sketch of contributions" (PDF). Caltech. Retrieved 9 June 2015.
- Mead, C. A. (1960). "The Tunnel-Emission Amplifier". Proceedings of the IRE 48 (3): 359–361. Retrieved 10 June 2015.
- Mead, C. A. (1 July 1962). "Transport of Hot Electrons in Thin Gold Films.". Physical Review Letters 9 (1): 46–46. doi:10.1103/PhysRevLett.9.46.
- Spitzer, W. G.; Mead, C. A. (1963). "Barrier Height Studies on Metal-Semiconductor Systems". Journal of Applied Physics 34 (10): 3061. doi:10.1063/1.1729121.
- Mead, C. A.; Spitzer, W. G. (4 May 1964). "Fermi Level Position at Metal-Semiconductor Interfaces". Physical Review 134 (3A): A713–A716. doi:10.1103/PhysRev.134.A713. Retrieved 10 June 2015.
- Wilmsen, Carl (2012). Physics and Chemistry of Iii-v Compound Semiconductor Interfaces. Springer Verlag. ISBN 978-1-4684-4837-5. Retrieved 10 June 2015.
- Mead, C.A. (1966). "Schottky barrier gate field effect transistor". Proceedings of the IEEE 54 (2): 307–308. doi:10.1109/PROC.1966.4661.
- Voinigescu, Sorin (2013). High-frequency integrated circuits. Cambridge: Cambridge University Press. pp. 254–264. ISBN 9780521873024. Retrieved 9 June 2015.
- Kanellos, Michael (March 9, 2005). "Moore says nanoelectronics face tough challenges". CNET News. Retrieved 4 June 2015.
- Moore, Gordon E. (1995). "Lithography and the future of Moore's law" (PDF). SPIE. Retrieved 2014-05-27.
- Brock, David C., ed. (2006). Understanding Moore's law : four decades of innovation. Philadelphia, Pa: Chemical Heritage Press. pp. 97–100. ISBN 0941901416.
- Gilder, George (July 5, 1999). "Carver Mead's fabulous camera". Forbes. Retrieved 9 June 2015.
- Kilbane, Doris (2005). "Carver Mead: A Trip Through Four Eras Of Innovation". Electronic Design. Retrieved 9 June 2015.
- Marshall, Martin; Waller, Larry; Wolff, Howard (October 20, 1981). "The 1981 Achievement Award". Electronics. Retrieved 4 June 2015.
- "Frederick B. Thompson 1922–2014". Caltech. Retrieved 10 June 2015.
- "Computer Science @ Caltech : History". 50th Anniversary Celebration. Retrieved 10 June 2015.
- Sutherland, Ivan E.; Mead, Carver A.; Everhart, Thomas E. (1976). R-1956-ARPA November 1976 Basic Limitations in Microcircuit Fabrication Technology. The Rand Corporation.
- Hiltzik, Michael A. (November 19, 2000). "Through the Gender Labyrinth". Los Angeles Times. Retrieved 9 June 2015.
- Hiltzik, Michael (2007). Dealers of lightning : Xerox PARC and the dawn of the computer age. New York: HarperBusiness. ISBN 9780887309892.
- Conway, Lynn. "Drafts of the Mead-Conway textbook, Introduction to VLSI Systems". University of Michigan. Retrieved 9 June 2015.
- THE MPC Adventures: Experiences with the Generation of VLSI Design and Implementation Methodologies, Lynn Conway, Xerox PARC Technical Report VLSI-81-2, January 19, 1981.
- THE MPC Adventures: Experiences with the Generation of VLSI Design and Implementation Methodologies, by Lynn Conway, Microprocessing and Microprogramming – The Euromicro Journal, Vol. 10, No. 4, November 1982, pp 209-228.
- "MPWs: Catalyst of IC Production Innovation". The MOSIS Service. Retrieved 9 June 2015.
- House, Chuck (2012). "A Paradigm Shift Was Happening All Around Us" (PDF). IEEE Solid State Circuits Magazine 4 (4): 32–35. Retrieved 10 June 2015.
- Allman, W.F. (October 21, 1991). "The man who crafts cathedrals of sand". U.S. News & World Report 111 (17): 80.
- Casale-Rossi, Marco; et. al. (18 March 2013). "Panel: The heritage of Mead & Conway What has remained the same, what was missed, what has changed, what lies ahead" (PDF). Design, Automation & Test in Europe Conference & Exhibition (DATE): 171 – 175. Retrieved 9 June 2015.
- Johannsen, D. L., "Bristle Blocks: A Silicon Compiler," Proceedings 16th Design Automation Conference, 310–313, June 1979.
- Lammers, David (April 30, 2015). "Moore’s Law Milestones". IEEE Spectrum.
- Cheng, Edmund; Fairbairn, Douglas (March 10, 2014). "Oral History of Edmund Cheng" (PDF). Computer History Museum. Retrieved 10 June 2015.
- Brown, Clair; Linden, Greg (2011). Chips and change : how crisis reshapes the semiconductor industry (1st ed.). Cambridge, Mass.: MIT Press. ISBN 9780262516822.
- Gilder, George (2005). The Silicon Eye: How a Silicon Valley Company Aims to Make All Current Computers, Cameras, and Cell Phones Obsolete (1st ed.). New York: W.W. Norton & Co. ISBN 978-0393057638.
- Indiveri, Giacomo; Horiuchi, Timothy K. (2011). "Frontiers in Neuromorphic Engineering". Frontiers in Neuroscience 5. doi:10.3389/fnins.2011.00118. Retrieved 10 June 2015.
- Mead, Carver (1989). Analog VLSI and neural systems. Reading, Mass.: Addison-Wesley. ISBN 978-0201059922.
- Markoff, John (December 28, 2013). "Brainlike Computers, Learning From Experience". The New York Times. Retrieved 8 June 2015.
- Reiss, Spencer (2004). "Carver Mead's Natural Inspiration" (PDF). Technology Review. Retrieved 2010-07-23.
- Markoff, John (October 24, 1994). "Pad to Replace Computer Mouse Is Set for Debut". The New York Times. Retrieved 10 June 2015.
- Diehl, Stanford; Lennon, Anthony J.; McDonough, John (Oct 1995). "Touchpads to Navigate By". Byte (Green Publishing) (October 1995): 150. ISSN 0360-5280.
- Lyon, R. F.; Mead, C. (1988). "An analog electronic cochlea". IEEE Trans. on Acoustics, Speech, and Signal Processing 36: 1119–1134. doi:10.1109/29.1639.
- Richard F. Lyon, "A Computational Model of Filtering, Detection, and Compression in the Cochlea", Proceedings IEEE International Conference on Acoustics, Speech, and Signal Processing, Paris, May 1982.
- Lyon, Richard F. (1991). "Analog implementations of auditory models". Proc. DARPA Workshop on Speech and Natural Language.
- Wen, Bo; Boahen, Kwabena (December 2009). "A Silicon Cochlea With Active Coupling". IEEE Transactions on Biomedical Circuits and Systems 3 (6): 444–455. doi:10.1109/TBCAS.2009.2027127.
- "Sonic Innovations Inc. History". Funding Universe. Retrieved 10 June 2015.
- Mahowald, Misha A.; Mead, Carver (May 1991). "The Silicon Retina". Scientific American 264 (5): 76–82. doi:10.1038/scientificamerican0591-76.
- "Milton and Francis Clauser Doctoral Prize". Retrieved 10 June 2015.
- "An incurable itch". Technology Quarterly (Q3). September 20, 2001. Retrieved 8 June 2015.
- Mead, Carver A. (2011). "Adaptive Retina". In Mead, Carver M.; Ismail, M. Analog VLSI Implementation of Neural Systems. Springer Verlag. ISBN 978-1-4612-8905-0.
- "Foveon X3 technology overview". Digital Photography Review. February 11, 2002.
- Peters, Mark (6 November 2005). "Royal Photographic Society Award for Foveon sensor".
- Diorio, C.; Hasler, P.; Minch, A.; Mead, C.A. (1995). "A single-transistor silicon synapse". IEEE Transactions on Electron Devices 43 (11): 1972–1980. doi:10.1109/16.543035.
- Hasler, P.; Diorio, C.; Minch, A.; Mead, C.A. (1999). "Single transistor learning synapse with long term storage". Proceedings of the 1995 IEEE International Symposium on Circuits and Systems 3: 1660–1663. doi:10.1109/ISCAS.1995.523729.
- Diorio, Chris; Hasler, Paul; Minch, Bradley A.; Mead, Carver (1998). "Floating-Gate MOS Synapse Transistors". In Lande, Tor Sverre. Neuromorphic systems engineering : neural networks in silicon. Boston, Massachusetts: Kluwer Academic. ISBN 978-0-7923-8158-7. Retrieved 9 June 2015.
- Mead, Carver M.; Ismail, M., eds. (2011). Analog VLSI Implementation of Neural Systems. (PDF). Springer Verlag. ISBN 978-1-4612-8905-0. Retrieved 9 June 2015.
- Hasler, Paul; Minch, Bradley A.; Diorio, Chris (1999). "Floating-gate devices: they are not just for digital memories any more" (PDF). ISCAS '99. Proceedings of the 1999 IEEE International Symposium on Circuits and Systems 2: 388–391. doi:10.1109/ISCAS.1999.780740. Retrieved 10 June 2015.
- Cauwenberghs, Gert; Bayoumi, Magdy A. (1999). Learning on silicon : adaptive VLSI neural systems. Boston: Kluwer Academic. ISBN 978-0-7923-8555-4. Retrieved 10 June 2015.
- "Veterans Affairs to Install RFID in Hospitals across America". Impinj. 14 June 2013.
- Mead, Carver (2002). Collective Electrodynamics: Quantum Foundations of Electromagnetism. MIT Press. ISBN 0-262-63260-8.
- "Impinj Adds New Piece Of The RFID Puzzle" (PDF). Scan: The Data Capture Report. February 28, 2014. Retrieved 4 June 2015.
- "BBVA Foundation Frontiers of Knowledge Award". Retrieved 4 June 2015.
- "President Bush Announces the Laureates of the 2002 National Medals of Science and Technology". The White House. October 22, 2003.
- Towey, Laine (March 8, 2002). "Microelectronics Pioneer Carver Mead Wins $47,000 Dickson Prize". Carnegie Mellon News. Carnegie Mellon University. Retrieved 4 June 2015.
- Newton, A. Richard (November 12, 1996). "Presentation of the 1996 Phil Kaufman Award to Professor Carver A. Mead". Berkeley Engineering.
- "Franklin Institute Honors Eight Physicists". Physics Today 38 (7): 84. 1985. doi:10.1063/1.2814644.
- "The Harold Pender Award". School of Engineering and Applied Science, University of Pennsylvania. Retrieved February 5, 2011.