@incollection{Hemmer1990,
  author    = {Ingrid Hemmer},
  title     = {Umwelterziehung},
  booktitle = {Didaktik der Geographie - Begriffe},
  edition   = {V{\"o}llig {\"u}berarb. Ausg.},
  editor    = {Dieter B{\"o}hn},
  isbn      = {978-3-486-88032-8},
  year      = {1990},
}