@TECHREPORT {,
  AUTHOR={},
  TITLE={{}},
  YEAR=,
  INSTITUTION={Sonderforschungsbereich 649, Humboldt Universit\"{a}t zu Berlin, Germany},
  TYPE={SFB 649 Discussion Paper},
  NOTE={available at http://sfb649.wiwi.hu-berlin.de/papers/pdf/},
  NUMBER={-}
}