The Free On-line Dictionary of Computing (30 December 2018):

Extended Concurrent Prolog

    (ECP) Concurrent Prolog with OR parallelism,
   set abstraction and meta-inference features.

   ["AND-OR Queuing in Extended Concurrent Prolog", J. Tanaka et
   al, Proc Logic Prog Conf '85, LNCS 193, Springer 1985].

   (1994-12-01)