@Proceedings{	  dh04,
  title		= "Proc. 21st Annual Symposium on Theoretical Aspects of
		  Computer Science (STACS'04), Montpellier (France)",
  address	= "Heidelberg",
  editor	= "Volker Diekert and Michel Habib",
  year		= "2004",
  volume	= "2996",
  publisher	= "Springer-Verlag",
  series	= "Lecture Notes in Computer Science",
  isbn		= "3-540-21236-1",
  doi		= "10.1007/b96012"
}