IC Prolog II
Imperial College Prolog. A Prolog with multi-threading, TCP primitives for interprocess communication, mailboxes, and an interface to Parlog.
ftp://doc.ic.ac.uk/computing/programming/languages.
["IC Prolog II: A Language for Implementing Multi-Agent Systems", Y. Cosmadopoulos et al, in Tutorial and Workshop on Cooperating Knowledge Based Systems, Keele U 1992].