Stein, L. A., "Imagination and Situated Cognition," Journal of Experimental and Theoretical Artificial Intelligence, 6, 393--407, 1994. Reprinted in Android Epistemology, K. M. Ford, C. Glymour, and P. J. Hayes, eds., AAAI Press/The MIT Press, 1995, pp. 167--182. Earlier version appears as MIT AI Lab Memo 1277, February 1991. (postscript, 722K).
Stein, L. A., "Representation and Reactive Systems." Unpublished manuscript.