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2. & Computers and thought. New York: McGraw-Hill, 1963.
3. & GPS, a program that simulates human thought. In (Ed.), Lernende automaten. Munich: Olden-bourg, 1961.
4. Reprinted in & (Eds.), Computers and thought. New York: McGraw-Hill, 1963, Pp. 279–292.
5. Minds and machines. In (Ed.), Dimensions of mind. New York: New York University Press, 1960, Pp. 148–179.