Parial order semantics for refinement of actions - neither necessary nor always sufficient but appropriate when used with care.

Rob J. van Glabbeek Ursula Goltz Parial order semantics for refinement of actions - neither necessary nor always sufficient but appropriate when used with care. 154-163 1989 38 Bulletin of the EATCS db/journals/eatcs/eatcs38.html#GlabbeekG89