@book{Strassner2012,
  author    = {Strassner, C},
  title     = {Inhalte und Umsetzung einer nachhaltigen Verpflegung.},
  volume    = {Band 1},
  editor    = {Roehl, R.},
  address   = {M{\"u}nster},
  pages     = {61 S.},
  year      = {2012},
  language  = {de}
}
@book{Strassner2012,
  author    = {Strassner, C},
  title     = {Sektoranalyse Außer-Haus-Markt Schwerpunkt Gemeinschaftsverpflegung.},
  volume    = {Band 2},
  editor    = {Roehl, R.},
  address   = {M{\"u}nster},
  pages     = {40 S.},
  year      = {2012},
  language  = {mul}
}