@incollection{Buchholz1999,
  author    = {Buchholz, Wolfgang},
  title     = {Einkaufsleistungen messen.},
  series = {Der Einkaufs- und Lagerwirtschaftsberater, 84. Erg{\"a}nzung},
  booktitle = {Der Einkaufs- und Lagerwirtschaftsberater, 84. Erg{\"a}nzung},
  address   = {Wiesbaden},
  pages     = {1 -- 26},
  year      = {1999},
  language  = {mul}
}
@incollection{Baaken1999,
  author    = {Baaken, Thomas},
  title     = {Simultaneous Marktforschung},
  series = {Pepels W. (Hrsg.): Handbuch Moderne Marktforschungs-Praxis},
  booktitle = {Pepels W. (Hrsg.): Handbuch Moderne Marktforschungs-Praxis},
  address   = {Kriftel},
  pages     = {770 -- 782.},
  year      = {1999},
  language  = {mul}
}
@incollection{Baaken1999,
  author    = {Baaken, Thomas},
  title     = {Simultaneous Marktforschung},
  series = {Handbuch Moderne Marktforschungs-Praxis},
  booktitle = {Handbuch Moderne Marktforschungs-Praxis},
  address   = {Kriftel},
  pages     = {. 770 -- 782.},
  year      = {1999},
  language  = {mul}
}