A Revised Version of ACT ONE. - Ingo Claßen (ADT, 1988)

Revised ACT ONE: Categorical Constructions for an Algebraic Specification Language. - Ingo Claßen (Categorial Methods in Computer Science, 1988)

Algebraic Concepts for Software Development in ACT ONE, ACT TWO and LOTOS (eingeladener Vortrag). - Hartmut Ehrig; Ingo Claßen; Paul Boehm; Werner Fey; Martin Korff; Michael Löwe (Software-Entwicklung, 1989)

Overview of algebraic specification languages, enviroments and tools, and algebraic specifications of software systems(Part 3). - Hartmut Ehrig; Ingo Claßen (Bull. EATCS, 1990)

Overview of Algebraic Specification Languages Environments and Tools, and Algebraic Specifications of Software Systems. - Hartmut Ehrig; Ingo Claßen (Bull. EATCS, 1990)

Introduction to Algebraic Specification. Part 1: Formal Methods for Software Development. - Hartmut Ehrig; Bernd Mahr; Ingo Claßen; Fernando Orejas (Comput. J., 1992)

Introduction to Algebraic Specification. Part 2: From Classical View to Foundations of System Specifications. - Hartmut Ehrig; Bernd Mahr; Ingo Claßen; Fernando Orejas (Comput. J., 1992)

An Object-Oriented Design for the ACT ONE Environment. - Martin Gogolla; Ingo Claßen (AMAST, 1993)

Compositionality of application oriented structuring mechanisms for algebraic specification languages with initial semantics. - Ingo Claßen (1993)

Algebraic Specification Techniques and Tools for Software Development: The Act Approach - Ingo Claßen; Hartmut Ehrig; Dietmar Wolz (World Scientific, 1993)

Overview of Algebraic Specification Languages, Environments and Tools, and Algebraic Specifications of Software Systems. - Hartmut Ehrig; Ingo Claßen (Current Trends in Theoretical Computer Science, 1993)

Graphical Support for Prototyping of Algebraic Specifications. - Roswitha Bardohl; Ingo Claßen (GI Jahrestagung, 1994)

Static and Dynamic Semantics of Entity-Relationship Models Based on Algebraic Methods. - Ingo Claßen; Michael Löwe; Susanne Waßerroth; Jan Wortmann (GI Jahrestagung, 1994)

Categorical Concepts for Parameterized Partial Specifications. - Ingo Claßen; Martin Große-Rhode; Uwe Wolter (Math. Struct. Comput. Sci., 1995)

ALPHA - A Class Library for a Metamodel Based on Algebraic Graph Theory. - Sebastian Erdmann; Ingo Claßen (AMAST, 1996)

CUI to GUI Migration: Static Analysis of Character-Based Panels. - Ingo Claßen; Klaus Hennig; Ingo Mohr; Michael Schulz (CSMR, 1997)

Towards evolutionary and adaptive workflow systems-infrastructure support based on Higher-Order Object Nets and CORBA. - Ingo Claßen; Herbert Weber; Yanbo Han (EDOC, 1997)

Design and Semantics of a Query Language for Multidimensional Data. - Ingo Claßen (ADBIS, 2010)