@InProceedings{	  dgp91,
  author	= "Volker Diekert and Paul Gastin and Antoine Petit",
  address	= "Heidelberg",
  booktitle	= "Proc. 16th Symposium on Mathematical Foundations of
		  Computer Science (MFCS'91), Kazimierz Dolny (Poland), 1991",
  editor	= "A. Tarlecki",
  volume	= "520",
  pages		= "131--140",
  publisher	= "Springer-Verlag",
  series	= "Lecture Notes in Computer Science",
  title		= "Recognizable complex trace languages",
  year		= "1991",
  doi		= "10.1007/3-540-54345-7_56"
}