Michael Sannella, <a href="http://www.cs.washington.edu/research/projects/weird/www/skyblue-uist-94.html"> "SkyBlue: A Multi-Way Local Propagation Constraint Solver for User Interface Construction"</a>, in <em>Proceedings of the 1994 ACM Symposium on User Interface Software and Technology</em>, pages 137-146.  </UL>
