1. Julesz, B., Bell System Tech. J., 39, 1125 (1960).
2. Hering, E., Outlines of a Theory of the Light Sense, Trans. from German original, of separate sections (Harvard University Press, 1964).
3. Ross, J., and Hogben, J. H., Vision Res. (in the press).
4. Uttal, W., Percept. and Psychophys., 6, 121 (1969).
5. Julesz, B., Foundations of Cyclopean Perception (University of Chicago Press, Chicago, 1971).