@TECHREPORT {SFB649DP2017-024,
  AUTHOR={Li, Yingxing and H\"{a}rdle, Wolfgang K. and Huang, Chen},
  TITLE={{Smooth Principal Component Analysis for High Dimensional Data}},
  YEAR=2017,
  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/SFB649DP2017-024.pdf},
  NUMBER={2017-024}
}