@book{PfeifferKnepper1999,
  author    = {Pfeiffer, Johann and Knepper, Ludger},
  title     = {Diplom-Ingenieur/Diplom-Ingenieurin (Fachhochschule) Maschinenbau Energie- und W{\"a}rmetechnik},
  publisher = {Bertelsmann},
  address   = {Bielefeld},
  pages     = {Losebl.-Ausg.},
  year      = {1999},
  language  = {de}
}
@article{PfeifferGauchelLuecke1999,
  author    = {Pfeiffer, Johann and Gauchel, Joachim and L{\"u}cke, Mathias},
  title     = {Genauigkeitsbetrachtungen in der CIM-Prozesskette},
  series = {4th International Scientific Colloquium CAx Techniques : proceedings of the 4th international scientific colloquium, Fachhochschule Bielefeld, Germany, September 13 - 15, 1999 / [organized in co-operation between Fachhochschule Bielefeld and Rzesz{\´o}w University of Technology ]. Ed. by Heinrich Ostholt},
  journal   = {4th International Scientific Colloquium CAx Techniques : proceedings of the 4th international scientific colloquium, Fachhochschule Bielefeld, Germany, September 13 - 15, 1999 / [organized in co-operation between Fachhochschule Bielefeld and Rzesz{\´o}w University of Technology ]. Ed. by Heinrich Ostholt},
  publisher = {[Fachhochsch.]},
  address   = {[Bielefeld]},
  isbn      = {3-00-004379-9},
  pages     = {323 -- 332},
  year      = {1999},
  language  = {de}
}
@book{Pfeiffer1999,
  author    = {Pfeiffer, Johann},
  title     = {Verbesserung der Qualit{\"a}t von Freiformoberfl{\"a}chen},
  publisher = {Fachhochsch.},
  address   = {Aachen},
  year      = {1999},
  language  = {de}
}
@book{KnepperPfeiffer1999,
  author    = {Knepper, Ludger and Pfeiffer, Johann},
  title     = {Diplom-Ingenieur / Diplom-Ingenieurin (Fachhochschule) Maschinenbau, Energie- und W{\"a}rmetechnik},
  publisher = {Bertelsmann},
  address   = {Bielefeld},
  pages     = {Loseblattausg.},
  year      = {1999},
  language  = {de}
}