with Luccio, R. , 1990, The phenomenology of autonomous order formation in perception, in H. Haken & M. Stadler (eds.), Synergetics of cognition, Dordrecht, Springer, pp. 186-200.
, 1979, Organization in vision: essays on Gestalt perception, Praeger, New York.
, 1975a, Some new demonstrations of the role of structural factors in brightness contrast, in S. Ertel, L. Kemmler & M. Stadler (eds.), Gestalttheorie in der Modernen Psychologie, Heidelberg, Steinkopff, pp. 219-226.