This is a partial list of the references that I used or found about this approach and related ideas. I intend to add more references as I find them in the future.

Atick, Joseph J, Paul A. Griffin, and A. Norman Redlich. "Face Recognition from Live Video for Real-World Applications--Now." Advanced Imaging May 1995: 58-60.

Benson, P. J., and D. I. Perrett "Extracting prototypical facial images from exemplars." Perception 22 (1993): 257-262.

Burt, D. Michael, and David I. Perrett, "Perception of age in adult Caucasian male faces: computer graphic manipulation of shape and colour information." Proc. R. Soc. London, 259 (1995): 137-143.

Dewdney, A. K., The Tinkertoy Computer. New York: Viking, 1995.

Galton, F. J. "Composite portraits." Nature, Lond. 18 (1878): 97-100.

Green, Bill. "Edgewarp code." Personal e-mail (17 April 1996).

Golub, G. H. and C. F. Loan. Matrix Computations. Baltimore: John Hopkins University Press, 1983.

Lee, Kieran, Dave Perrett, Duncan Rowland, and Mike Burt. "Facial Prototyping." (30 April 1996).

Perrett, D. I., K. A. May, and S. Yoshikawa. "Facial shape and judgements of female attractiveness." Nature 368 (17 March 1994): 239-242.

Rowland, Duncan A. "Pulling Faces" SIGGRAPH Technical Sketch Lecture. 9 August 1995.

Ruprecht, Detlef, and Heinrich Muller. "Image Warping with Scattered Data Interpolation Methods." Technical Report, Universitat Dortmund. 6 November 1992.