@book{Hegewald1987,
  author    = {Hegewald, Ulf},
  title     = {Ulf Hegewald / hrsg. von Marianne Hennemann},
  publisher = {Galerie Hennemann},
  address   = {Bonn},
  isbn      = {3-88482-032-X},
  pages     = {88 S. : {\"u}berw. Ill.},
  year      = {1987},
  language  = {de}
}
@book{Maether1987,
  author    = {Maether, Christiane},
  title     = {Zeichnung und Malerei / Text: Wolfgang Becker},
  address   = {Aachen},
  pages     = {71 S.: {\"u}berw. Ill.},
  year      = {1987},
  language  = {de}
}