QPE

1. A two-dimensional pictorial query language.

["Pictorial Information Systems", S.K. Chang et al eds, Springer 1980].

[Q-systems. A. Colmerauer, 1969].

2. A rewrite system with one-way unification, used for English-French translation. It led to Prolog.

["The Birth of Prolog" A. Colmerauer et al, SIGPLAN Notices 28(3):37-52 March 1993].