Constraint Handling In Prolog
(CHIP) A constraint logic programming language developed by M. Dincbas at ECRC, Munich, Germany in 1985 which includes Boolean unification and a symbolic simplex-like algorithm. CHIP introduced the domain-variable model.
["The Constraint Logic Programming Language CHIP", M. Dincbas et al, Proc 2nd Intl Conf on Fifth Generation Computer Sys, Tokyo (Nov 1988), pp.249-264].
["Constraint Satisfaction in Logic Programming", Van Hentenryck. Available from COSYTEC, 4 rue Jean Rostand, F91893 Orsay, France].