Hall, A.D. "The ALTRAN System for Rational Function Manipulation: A Survey" pp153-157

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

Languages mentioned ALTRAN {1969} A FORTRAN extension for rational algebra