@book{Pfeiffer2003,
  author    = {Pfeiffer, Johann},
  title     = {3D-Freiformfl{\"a}chenmessung},
  publisher = {Fachhochsch.},
  address   = {Aachen},
  year      = {2003},
  language  = {de}
}
@book{Pfeiffer1996,
  author    = {Pfeiffer, Johann},
  title     = {Automatisierung in der Handhabungs- und Montagetechnik},
  publisher = {Fachhochsch.},
  address   = {Aachen},
  year      = {1996},
  language  = {de}
}
@article{Pfeiffer2002,
  author    = {Pfeiffer, Johann},
  title     = {Chancen im Maschinenbau},
  series = {Fachblatt : Journal der Fachhochschule Aachen . 2002 (2002), H. 1},
  journal   = {Fachblatt : Journal der Fachhochschule Aachen . 2002 (2002), H. 1},
  publisher = {-},
  pages     = {2},
  year      = {2002},
  language  = {de}
}
@book{Pfeiffer1997,
  author    = {Pfeiffer, Johann},
  title     = {Design und Herstellen von Werkzeugen mit Freiformfl{\"a}chen},
  publisher = {Fachhochsch.},
  address   = {Aachen},
  year      = {1997},
  language  = {de}
}
@book{PfeifferKnepper1998,
  author    = {Pfeiffer, Johann and Knepper, Ludger},
  title     = {Diplom Ingenieur/Diplom Ingenieurin (Fachhochschule) Maschinenbau Konstruktionstechnik},
  publisher = {Bertelsmann},
  address   = {Bielefeld},
  pages     = {Losebl.-Ausg.},
  year      = {1998},
  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}
}
@book{PfeifferKnepper1995,
  author    = {Pfeiffer, Johann and Knepper, Ludger},
  title     = {Diplom-Ingenieur/Diplom-Ingenieurin ( Fachhochschule ) Maschinenbau - Allgemeiner Maschinenbau},
  publisher = {Bertelsmann},
  address   = {Bielefeld},
  pages     = {Losebl.-Ausg.},
  year      = {1995},
  language  = {de}
}
@book{KnepperPfeiffer1995,
  author    = {Knepper, Ludger and Pfeiffer, Johann},
  title     = {Diplom-Ingenieur/Diplom-Ingenieurin (Fachhochschule) Maschinenbau - Allgemeiner Maschinenbau},
  publisher = {Bertelsmann},
  address   = {Bielefeld},
  pages     = {Loseblattausg.},
  year      = {1995},
  language  = {de}
}
@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}
}
@book{KnepperPfeiffer1998,
  author    = {Knepper, Ludger and Pfeiffer, Johann},
  title     = {Diplom-Ingenieur/Diplom-Ingenieurin (Fachhochschule) Maschinenbau Konstruktionstechnik},
  publisher = {Bertelsmann},
  address   = {Bielefeld},
  pages     = {Loseblattausg.},
  year      = {1998},
  language  = {de}
}