@unpublished{BollinKuttruff,
  author    = {Bollin, Elmar and Kuttruff, Ulrich},
  title     = {Kraft-W{\"a}rme-K{\"a}lte-Kopplung in der neuen Energiezentrale f{\"u}r die Hochschule Offenburg},
  series = {Horizonte : Forschung an Fachhochschulen in Baden-W{\"u}rttemberg},
  volume    = {33},
  number    = {Januar 2009},
  issn      = {1432-9174},
  language  = {de}
}
@unpublished{SikorskiKuttruff,
  author    = {Sikorski, Evgenia and Kuttruff, Ulrich},
  title     = {Organisation und Finanzierung von Exkursionen},
  series = {Die neue Hochschule},
  volume    = {52},
  number    = {4-5},
  issn      = {0340-448X},
  pages     = {194 -- 195},
  language  = {de}
}
@unpublished{SikorskiKuttruff,
  author    = {Sikorski, Evgenia and Kuttruff, Ulrich},
  title     = {Einblick in die deutsche TGA-Landschaft. Energietechniker der Hochschule Offenbach auf Exkursion},
  series = {Tab - Das Fachmedium der TGA-Branche},
  volume    = {42 2011},
  number    = {11},
  issn      = {0341-2032},
  pages     = {59},
  language  = {de}
}