@TechReport{Blumensath01,
  author =       "Achim Blumensath",
  title =        "Prefix-Recognisable Graphs and Monadic Second-Order Logic",
  institution =  "RWTH Aachen",
  year =         "2001",
  number =       "AIB-06-2001",
  month =        may,
  url =          "http://aib.informatik.rwth-aachen.de/2001/2001-06.ps.gz",
}