microPLANNER
G. J. Sussman et al, MIT
A subset of PLANNER, implemented in LISP. Superseded by CONNIVER. Among its important features: goal-oriented, pattern-directed procedure invocation, embedded knowledge base, automatic backtracking.
"microPLANNER Reference Manual", G. J. Sussman et al, AI Memo 203, MIT AI Lab, 1970.