@book{Maether1991,
  author    = {Maether, Christiane},
  title     = {Figur und Fragment : Gem{\"a}lde und Zeichnungen 1985-1990},
  address   = {Kaiserslautern},
  isbn      = {3-89422-039-2},
  pages     = {94 S. : {\"u}berw. Ill.},
  year      = {1991},
  language  = {de}
}
@book{OPUS4-1635,
  title     = {Joseph Beuys : Natur, Materie, Form},
  editor    = {Zweite, Armin},
  publisher = {Schirmer/Mosel},
  address   = {M{\"u}nchen [u.a.]},
  isbn      = {3-88814-453-1},
  pages     = {360 S. : {\"u}berw. Ill.},
  year      = {1991},
  language  = {de}
}
@book{Hegewald1991,
  author    = {Hegewald, Ulf},
  title     = {Plastiken 91 / Xylon, Museum + Werkst{\"a}tten},
  address   = {Schwetzingen},
  pages     = {34 S. : {\"u}berw. Ill.},
  year      = {1991},
  language  = {de}
}
@book{FaboEisenbeisHageboelling1991,
  author    = {Fabo, Sabine and Eisenbeis, Manfred and Hageb{\"o}lling, Heide},
  title     = {Projekt f{\"u}r die Gr{\"u}ndung eines Internationalen Zentrums f{\"u}r Kunst und Medien : M{\"o}glichkeitsstudie f{\"u}r die UNESCO},
  publisher = {Kunsthochschule f{\"u}r Medien K{\"o}ln},
  address   = {K{\"o}ln},
  year      = {1991},
  language  = {de}
}