@Article{	  die90tcs,
  author	= "Volker Diekert",
  journal	= "Theoretical Computer Science",
  pages		= "3--18",
  title		= "Word problems over traces which are solvable in linear
		  time",
  volume	= "74",
  year		= "1990",
  note		= "Revised and extended version of \cite{die89}, Special
		  issue STACS~89",
  doi		= "10.1016/0304-3975(90)90003-Z"
}