@book{BerndtWipper1993,
  author    = {Klaus-Peter Berndt and Renate Wipper},
  title     = {Umwelterziehung},
  editor    = {Klaus-Peter Berndt and Erich Sch{\"a}fer},
  isbn      = {3-929757-18-4},
  year      = {1993},
}