1. M-expression LISP .
2. Meta-LISP. D.C. Smith & H. Enea. LISP variant with ALGOL-like syntax. Not just a surface syntax, a full language.
"MLISP", D.C. Smith, TR CS-179, CS Dept, Stanford (Oct 1970). Version: MLISP2.
3. A hybrid of M-expression LISP and Scheme.
"M-LISP: Its Natural Semantics and Equational Logic", R. Muller, SIGPLAN Notices 26(9):234-242 (Sept 1991) (PEPM '91).