In: Proceedings of the ACM SIGOIS and IEEE CS TC-OA conference on Office Information Systems. International Conference on Office Automation Systems (COIS-90), April 25-27, Cambridge, MA, USA, Pages 118-122, ISBN 0-89791-358-2, ACM, New York, NY, USA, 4/1990.
In: Proceedings SSPR90. International Workshop on Structural and Syntactic Pattern Recognition (SSPR-90), June 13-15, Murray Hill, NJ, USA, Pages 78-87, 6/1990.
In: Rudolf E. Großkopf (Hrsg.). Mustererkennung 1990 - Proceedings of the 12. DAGM-Symposium. Annual Symposium of the German Association for Pattern Recognition (DAGM-90), 12th, September 24-26, Oberkochen-Aalen, Germany, Pages 130-137, Informatik Fachberichte, Vol. 254, ISBN 3-540-53172-6, Springer, London, 1990.