1. A polymorphic, block-structured language developed by D.C.J. Matthews at Cambridge in the early 1980s.

["An Overview of the Poly Programming Language", D.C.J. Matthews, in Data Types and Persistence, M.P. Atkinson et al eds, Springer 1988].

2. A language developed at Saint Andrews University, Scotland.

[Software Practice & Exp, Oct 1986].

3. A polymorphic language used in the referenced book.

["Polymorphic Programming Languages", David M. Harland, Ellis Horwood 1984].