1. Lect Notes Comput Sci;E. Best,1992
2. Lect Notes Comput Sci;E. Best,1995
3. E. Best and B. Grahlmann. PEP: Documentation and User Guide. Universität Hildesheim. Available together with the tool via:
http://theoretica.informatik.uni-oldenburg.de/~pep
.
4. Lect Notes Comput Sci;E. Best,1993
5. Lect Notes Comput Sci;A. Bouali,1996