@incollection{BERNHOLDKALINGLELLEK2011,
  author    = {BERNHOLD, T. and KALING, N. and LELLEK, V.},
  title     = {Produktivit{\"a}tsmessung von Dienstleistungen},
  series = {BERNHOLD, T.; GELLENBECK, K.; RIEMENSCHNEIDER, F., M{\"u}nsteraner Schriften zum Facility Management},
  booktitle = {BERNHOLD, T.; GELLENBECK, K.; RIEMENSCHNEIDER, F., M{\"u}nsteraner Schriften zum Facility Management},
  publisher = {INFA-ISFM e.V.},
  address   = {M{\"u}nster, Ahlen},
  pages     = {108 -- 122},
  year      = {2011},
  language  = {de}
}
@misc{BERNHOLDKALINGLELLEK2011,
  author    = {BERNHOLD, T. and KALING, N. and LELLEK, V.},
  title     = {Measurement of productivity of property services: an empiric analysis of the status quo, XXI. International RESER Conference, Hamburg, 07.09.-10.09.2011 2011},
  year      = {2011},
  language  = {en}
}