Wikipedia
MATHLAB
MATHLAB is a computer algebra system created in 1964 by Carl Engelman at MITRE and written in LISP.
"MATHLAB 68" was introduced in 1967 and became rather popular in university environments running on DECs PDP-6 and PDP-10 under TOPS-10 or TENEX. In 1969 this version was included in the DECUS user group's library (as 10-142) as royalty-free software.
Carl Engelman left MITRE for Symbolics where he contributed his expert knowledge in the development of Macsyma.