Rob J. van Glabbeek Ursula Goltz Refinement of actions and equivalence notions for concurrent systems. 229-327 2001 37 Acta Inf. 4/5 http://link.springer.de/link/service/journals/00236/bibs/1037004/10370229.htm db/journals/acta/acta37.html#GlabbeekG01