Xuan-Ha Vu Hermann Schichl Djamila Sam-Haroud Using Directed Acyclic Graphs to Coordinate Propagation and Search for Numerical Constraint Satisfaction Problems. 72-81 2004 conf/ictai/2004 ICTAI http://doi.ieeecomputersociety.org/10.1109/ICTAI.2004.118 db/conf/ictai/ictai2004.html#VuSS04