OPAL: Design and Implementation of an Algebraic Programming Language. - Klaus Didrich; Andreas Fett; Carola Gerke; Wolfgang Grieskamp; Peter Pepper (Programming Languages and System Architectures, 1994)

Realizing Sets by Hash Tables. - Peter Pepper; Ralph Betschko; Sabine Dick; Klaus Didrich (KORSO Book, 1995)

How to Cope with the Spectrum of SPECTRUM. - Uwe Wolter; Klaus Didrich; Felix Cornelius; Marcus Klar (KORSO Book, 1995)

Towards Integrating Algebraic Specification and Functional Programming: the Opal System (Extended Abstract). - Klaus Didrich; Carola Gerke; Wolfgang Grieskamp; Christian Maeder; Peter Pepper (AMAST, 1996)

Programming in the Large: The Algebraic-Functional Language Opal 2alpha. - Klaus Didrich; Wolfgang Grieskamp; Christian Maeder; Peter Pepper (Implementation of Functional Languages, 1997)

DOSFOP - A Documentation Tool for the Algebraic Programming Language OPAL. - Klaus Didrich; Torsten Klein (TAPSOFT, 1997)

Reflections in Opal - Meta Information in a Functional Programming Language. - Klaus Didrich; Wolfgang Grieskamp; Florian Schintke; Till Tantau; Baltasar Trancón y Widemann (IFL, 1999)

Integration of verification and testing into compilation systems: concept and case study. - Klaus Didrich (2001)

From program languages to software languages. - Peter Pepper; Michael Cebulla; Klaus Didrich; Wolfgang Grieskamp (J. Syst. Softw., 2002)

Appyling Model-based Testing to a Train Control System. - Klaus Didrich; Stefan Herbst; Marlon Vieira (GI Jahrestagung (2), 2006)