@article{KummerKuemmerlingRaetzeletal.1995,
  author    = {Kummer, Volker and K{\"u}mmerling, Heidi and R{\"a}tzel, Stefan and Otte, Volker},
  title     = {Bemerkenswerte Flechtenfunde aus Brandenburg : eine Anregung zur floristischen Arbeit},
  year      = {1995},
  language  = {de}
}
@article{OtteRaetzelKummer1997,
  author    = {Otte, Volker and R{\"a}tzel, Stefan and Kummer, Volker},
  title     = {Bemerkenswerte Flechtenfunde aus Brandenburg III},
  year      = {1997},
  language  = {de}
}
@article{OtteRaetzelSipmanetal.2000,
  author    = {Otte, Volker and R{\"a}tzel, Stefan and Sipman, Harri J. M. and Kummer, Volker},
  title     = {Bemerkenswerte Flechtenfunde aus Brandenburg V},
  year      = {2000},
  language  = {de}
}
@article{OtteRaetzelKummeretal.2001,
  author    = {Otte, Volker and R{\"a}tzel, Stefan and Kummer, Volker and De Bruyn, Uwe},
  title     = {Bemerkenswerte Flechtenfunde aus Brandenburg VI},
  year      = {2001},
  language  = {de}
}
@article{RaetzelKummerOtteetal.2002,
  author    = {R{\"a}tzel, Stefan and Kummer, Volker and Otte, Volker and Sipman, Harri J. M},
  title     = {Bemerkenswerte Flechtenfunde aus Brandenburg VII},
  year      = {2002},
  language  = {de}
}
@article{SeitzRistowKlemmetal.2004,
  author    = {Seitz, Birgit and Ristow, Michael and Klemm, Gunther and R{\"a}tzel, Stefan and Schulze, Gerhart and Hoffmann, Maik},
  title     = {Zur Verbreitung der Wildrosen und verwilderten Kulturrosen in Berlin und Brandenburg},
  issn      = {0724-3111 -},
  year      = {2004},
  language  = {de}
}