Clapp, L. C. and Kain, R. Y. "A computer aid for symbolic mathematics"

(1963)

[AFIPS JCC 24] Proceedings of the 1963 Fall Joint (1963) [AFIPS JCC 24] Proceedings of the 1963 Fall Joint Computer Conference FJCC 1963, Las Vegas, Nev., Nov. 1963,  

Languages mentioned