M. Gyssens, J. Paredaens, and D. Gucht. Proc. of the 9th Symposium on Principles of Database Systems (PODS 1990), page 417--424. Nashville TN, USA, (April 1990)
B. Kuijpers, J. Paredaens, and J. den Bussche. Proc. of the Workshop on Finite Model Theory and its Applications at FLoC 1999, eds. Michael Benedikt, Leonid Libkin, Jouku Vaananen, Trento (Italy), (1999)
C. Tuijn, M. Gyssens, and J. Paredaens. Third Workshop on Foundations of Models and Languages for Data and Objects, 91/3, page 187--196. Aigen, Austria, (September 1991)
J. Hidders, J. Paredaens, R. Vercammen, and S. Demeyer. Proceedings of Second International XML Database Symposium, volume 3186 of Lecture Notes in Computer Science, page 5-20. Toronto, Canada, Springer-Verlag, (August 2004)