Alan Borning and Bjorn N. Freeman-Benson,  <a href="http://www.cs.washington.edu/research/projects/weird/www/ultraviolet-cp-95.html"> "The OTI Constraint Solver: A Constraint Library for Constructing Interactive Graphical User Interfaces"</a>,  <em>Proceedings of the First International Conference on Principles and Practice of Constraint Programming</em>, September 1995, pages 624-628.  <LI>
