@Article{	  dgh01arxiv,
  title		= "The Existential Theory of Equations with Rational
		  Constraints in Free Groups is PSPACE-Complete",
  journal	= "Computing Research Repository (arXiv eprints)",
  year		= "2001",
  volume	= "cs.DS/0103018",
  author	= "Diekert, Volker and Guti{\'e}rrez, Claudio and Hagenah,
		  {\relax Ch}ristian"
}