@TechReport{BolligLeucker01,
  author =       "Martin Grohe and Stefan W\"ohrle",
  title =        "An Existential Locality Theorem",
  institution =  "RWTH Aachen",
  year =         "2001",
  number =       "AIB-07-2001",
  month =        june,
  url =          "http://aib.informatik.rwth-aachen.de/2001/2001-07.ps.gz",
}