Heinrich Hussmann

Birgit Demuth, Heinrich Hussmann: Using UML/OCL Constraints for Relational Database Design, Second International Conference on the Unified Modeling Language: UML'99, 1999, (BibTeX entry).
Heinrich Hussmann, Birgit Demuth, Frank Finger: Modular Architecture for a Toolset Supporting OCL, Third International Conference on the Unified Modeling Language: UML 2000, 2000, (BibTeX entry).
Birgit Demuth, Heinrich Hussmann, Sten Loecher: OCL as a Specification Language for Business Rules in Database Applications, Fourth International Conference on the Unified Modeling Language: UML 2001, 2001, (BibTeX entry).
Rolf Hennicker, Heinrich Hussmann, Michel Bidoit: On the Precise Meaning of OCL Constraints, Springer, 2002, (BibTeX entry).
Gianna Reggio, Egidio Astesiano, Christine Choppy, Heinrich Hussmann: Analysing UML Active Classes and Associated State Machines -- A Lightweight Formal Approach, Springer, 2000, (BibTeX entry).

dblp: Computer Science Bibliography (University of Trier, Germany). (Note that this does not always work due to different naming schemes.)