@Article{	  die90bull,
  author	= "Volker Diekert",
  journal	= "Bulletin of the European Association for Theoretical
		  Computer Science (EATCS)",
  month		= "2",
  pages		= "479--491",
  title		= "Research topics in the theory of free partially
		  commutative monoids",
  volume	= "40",
  year		= "1990"
}