books.google.at - Constraint satisfaction is a simple but powerful tool. Constraints identify the impossible and reduce the realm of possibilities to effectively focus on the possible, allowing for a natural declarative formulation of what must be satisfied, without expressing how. The field of constraint reasoning has...http://books.google.at/books/about/Constraint_Porcessing.html?hl=de&id=1mJSHuOS0UcC&utm_source=gb-gplus-shareConstraint Porcessing
