Carola Gerke

OPAL: Design and Implementation of an Algebraic Programming Language

Wolfgang Grieskamp, Peter Pepper, Klaus Didrich, 1994, Programming Languages and System Architectures.

Korso Reference Languages - Concepts and Application Domains

Martin Gogolla, Ernst-Rüdiger Olderog, Grit Denker, 1995, KORSO Book.

Towards Integrating Algebraic Specification and Functional Programming: the Opal System (Extended Abstract)

Wolfgang Grieskamp, Peter Pepper, Klaus Didrich, 1996, AMAST.