1. Drumheller, M. & Poggio, T. in Proc. IEEE Conf. on Robotics and Automation 1439–1448 (1986).
2. Poggio, T. et al. in Proc. Image Understanding Workshop (Morgan Kaufmann, San Mateo, California, 1988).
3. Bülthoff, H. H., Little, J. J. & Poggio, T. J. opt. Soc. Am. 4, 34 (1987).
4. Hildreth, E. C. The Measurement of Visual Motion (MIT, Cambridge, Massachusetts, 1984).
5. Nakayama, K. & Silverman, G. H. Vision Res. 28, 739–746 (1988).