Michael Sannella, <a href="http://www.cs.washington.edu/research/projects/weird/www/skyblue-ppcp-93.html"> "The Skyblue Constraint Solver and Its Applications"</a>, Vijay Saraswat and Pascal van Hentenryck, editors, Proceedings of the 1993 Workshop on Principles and Practice of Constraint Programming, MIT Press, 1995, pages 385-406.  <LI>
