BABEL[3]

A higher-order functional language with first-order logic.

"Graph-Based Implementation of a Functional Logic Language", H. Kuchen et al, Proceedings of ESOP 90, Lecture Notes in Computer Science 432, Springer-Verlag, 1990, pp.271-290.

"Logic Programming with Functions and Predicates: The Language BABEL", Moreno-Navarro et al, Journal of Logic Programming 12(3) (Feb 1992).