Source : Free On-Line Dictionary of Computing

EQLOG
     
        Equality, types and generic modules for logic programming.
        A language using Horn clauses.  J.A. Goguen, J. Meseguer.

EQLog
     
        OBJ2 plus logic programming based on Horn logic with equality.
     
        "EQLog: Equality, Types and Generic Modules for Logic
        Programming", J.  Goguen et al in Functional and Logic
        Programming, D. DeGroot et al eds, pp.295-363, P-H 1986.