1. Sociological;Axten,1977
2. & Roles and role-programs. Quality and Quantity, forthcoming.
3. & The structure of social systems. New York: Gardner Press (distributed by Halsted Press, N. Y.), 1975.
4. & Formal languages and their relation to automata. Boston: Addison-Wesley, 1969.
5. & Finitary models of language users. In , , & (Eds.), Handbook of mathematical psychology (Vol. 1). New York: Wiley, 1963, pp. 419–491.