Martin, W. A.; Fateman, R. J. "The MACSYMA system" pp59-75

[SYMSAM 71] (1971) [ACM] Proceedings of the Second Symposium on Symbolic and Algebraic Manipulation, March 23-25, 1971 Los Angeles (SYMSAM 71)  

Languages mentioned MACSYMA {1969} Symbolic math system