1. A. Aiken and E. Wimmers. Solving systems of set constraints. In Symposium on Logic in Computer Science, pages 329–340, June 1992.
2. P. Arenas-Sanchez and A. Dovier. A minimality study for set unification. Journal of Functional and Logic Programming, 1997(7), 1997.
3. Lect Notes Comput Sci;R. D. Arthan,1998
4. R. Büssow and W. Grieskamp. The ZETA System Documentation. Technische Universität Berlin, Dec. 1998. URL: http://uebb.cs.tu-berlin.de/zeta .
5. R. Büssow and W. Grieskamp. A Modular Framework for the Integration of Heterogenous Notations and Tools. In K. Araki, A. Galloway, and K. Taguchi, editors, Proc. of the 1st Intl.Conference on Integrated Formal Methods-IFM’99. Springer-Verlag, London, June 1999.