Bayard H.A. et al, "The TREET Time-Sharing System"

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

Languages mentioned BAL {1971} IBM 360 assembly language TAP {1971} Macroassembler for the TREET system TREET {1964} trinary tree variant of LISP TROL {1971}