@techreport{GUM-2-0,
  author	= {Bateman, John A. and Henschel, Renate and Rinaldi, Fabio},
  year		= {1995},
  title		= {Generalized Upper Model 2.0: documentation},
  address	= {Darmstadt, Germany},
  institution	= {GMD/Institut f{\"u}r Integrierte Publikations- und Informationssysteme},
  URL		= {http://purl.org/net/gum2},
  urlpage	= {http://purl.org/net/gum2}
}