@misc{BERNHOLDKALINGLELLEK2011,
  author    = {BERNHOLD, T. and KALING, N. and LELLEK, M.},
  title     = {Measurement of productivity of property services: an empiric analysis of the status quo, XXI. International RESER Conference, Hamburg, 07.09.-10.09.2011},
  year      = {2011},
  language  = {en}
}
@incollection{BERNHOLDKALINGLELLEK2011,
  author    = {BERNHOLD, T. and KALING, N. and LELLEK, M.},
  title     = {Produktivit{\"a}tsmessung von Dienstleistungen},
  series = {BERNHOLD, T.; GELLENBECK, K.; RIEMENSCHNEIDER, F., M{\"u}nsteraner Schriften zum Faclity Management},
  booktitle = {BERNHOLD, T.; GELLENBECK, K.; RIEMENSCHNEIDER, F., M{\"u}nsteraner Schriften zum Faclity Management},
  publisher = {INFA-ISFM e.V.},
  address   = {M{\"u}nster, Ahlen},
  isbn      = {978-3-00-036210-1},
  pages     = {108 -- 122},
  year      = {2011},
  language  = {de}
}
@incollection{BERNHOLDKALINGLELLEK2011,
  author    = {BERNHOLD, T. and KALING, N. and LELLEK, M.},
  title     = {Measurement of productivity of property services - an empiric analysis of the status quo},
  series = {GANZ, W.; KIRCHERER, F.; SCHLETZ, A. (Hrsg.); Productivity of Services NextGen - Beyond Output/Input},
  booktitle = {GANZ, W.; KIRCHERER, F.; SCHLETZ, A. (Hrsg.); Productivity of Services NextGen - Beyond Output/Input},
  edition   = {1. Aufl.},
  publisher = {Fraunhofer Verlag},
  address   = {Stuttgart},
  isbn      = {978-3-8396-0297-3},
  pages     = {190 -- 191},
  year      = {2011},
  language  = {en}
}