Nakayama, K. (1999). Mid-level vision. In R. A. Wilson & F. C. Keil (Eds.), The MIT encylopedia of the cognitive sciences Cambridge: MIT Press
Nakayama, K. , He, Z.J. and Shimojo, S. Visual surface representation: a critical link between lower-level and higher level vision. In Kosslyn, S.M. and Osherson, D.N. Vision. In Invitation to Cognitive Science. M.I.T. Press, p. 1-70, 1995
http://www.visionlab.harvard.edu/Members/Ken/nakayamapub.htm