@book{Westerheide1973,
  author    = {Westerheide, Peter},
  title     = {Ausgew{\"a}hlte Verfahren zur Bestimmung des Belegungsgrades in Schienensystemen (Bahnstrecke Dortmund-Hamm)},
  address   = {M{\"u}nster},
  year      = {1973},
  language  = {de}
}
@book{WesterheideGarus1985,
  author    = {Westerheide, Peter and Garus, Guntram},
  title     = {Differential- und Integralrechnung},
  edition   = {1. Aufl.},
  publisher = {Hanser},
  address   = {M{\"u}nchen [u.a.]},
  isbn      = {3-446-13038-1},
  pages     = {250 S. : graph. Darst.},
  year      = {1985},
  language  = {de}
}
@book{Westerheide1985,
  author    = {Westerheide, Peter},
  title     = {Differential- und Integralrechnung (Analysis)},
  publisher = {Hanser-Verlag},
  address   = {M{\"u}nchen},
  isbn      = {3-446-13038-1},
  year      = {1985},
  language  = {de}
}
@book{Westerheide1987,
  author    = {Westerheide, Peter},
  title     = {Ranglistenberechnung per Computer},
  address   = {Hamburg},
  year      = {1987},
  language  = {mul}
}