@TECHREPORT {SFB649DP2016-023,
  AUTHOR={Fang, Lei and H\"{a}rdle, Wolfgang K. and Park, Juhyun},
  TITLE={{A Mortality Model for Multi-populations: A Semi-Parametric Approach}},
  YEAR=2016,
  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/SFB649DP2016-023.pdf},
  NUMBER={2016-023}
}