@TECHREPORT {SFB649DP2015-050,
  AUTHOR={Breunig, Christoph and Mammen, Enno and Simoni, Anna},
  TITLE={{Nonparametric Estimation in case of Endogenous Selection}},
  YEAR=2015,
  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/SFB649DP2015-050.pdf},
  NUMBER={2015-050}
}