Information Hiding and the Complexity of Constraint Satisfaction. - Remco C. Veltkamp; Richard H. M. C. Kelleners (Eurographics Workshop on Programming Paradigms in Graphics, 1995)

Using 3D Geometric Constraints in Architectural Design Support Systems. - Bert de Vries; A. Joran Jessurun; Richard H. M. C. Kelleners (WSCG, 2000)