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 St 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].