@article{OswaldKrappmann1995,
  author    = {Oswald, Hans and Krappmann, Lothar},
  title     = {Unsichtbar durch Sichtbarkeit : der teilnehmende Beobachter im Klassenzimmer},
  year      = {1995},
  language  = {de}
}
@article{OswaldKrappmann1995,
  author    = {Oswald, Hans and Krappmann, Lothar},
  title     = {Social life of children in a former bipartite city},
  year      = {1995},
  language  = {en}
}