@book{Maether1987,
  author    = {Maether, Christiane},
  title     = {Zeichnung und Malerei / Text: Wolfgang Becker},
  address   = {Aachen},
  pages     = {71 S.: {\"u}berw. Ill.},
  year      = {1987},
  language  = {de}
}
@book{Hegewald1999,
  author    = {Hegewald, Ulf},
  title     = {Ziegelfeld am Keramion, Frechen ; 16.5.1999 - 30.9.2000, Keramion, Museum f{\"u}r zeitgen{\"o}ssische keramische Kunst},
  address   = {Frechen},
  pages     = {95 S. : zahlr. Ill., graph. Darst.},
  year      = {1999},
  language  = {de}
}