L. Aarts, and P. der Veer. International Conference on Computational Science (2), volume 2074 of Lecture Notes in Computer Science, page 181-189. Springer, (2001)
G. van der Veer, J. van Beek, and G. Cruts. Informatics and Psychology Workshop, volume 282 of Lecture Notes in Computer Science, page 70-88. Springer, (1986)