Computer Dictionary/Concurrent Prolog
A Prolog variant with guarded clauses and committed-choice nondeterminism ([[Computer Dictionary/don't-care nondeterminism|don't-care nondeterminism]]) by Ehud "Udi" Shapiro, Yale email@example.com. A subset has been implemented, but not the full language.
See also Mandala.
["Concurrent Prolog: Collected Papers", E. Shapiro, V.1-2, MIT Press 1987].