@InProceedings{ctcs04,
  author = 	 {A. Sokolova and Vink, E.P. de and H. Woracek},
  title = 	 {Weak Bisimulation for Action-Type Systems}, 
  booktitle = 	 {Proc.\ CTCS 2004},
  editor =       {L. Birkedal},
  publisher =	 {ENTCS~122},
  year =	 2005,
  note =	 {211--228}
}