@article{Alpers1994,
  author    = {Alpers, Karsten},
  title     = {{\"U}ber zweidimensionale diskrete Bewegungsgruppen der pseudoeuklidischen Ebene},
  year      = {1994},
  language  = {de}
}
@book{AlpersDietzschEppetal.2004,
  author    = {Alpers, Karsten and Dietzsch, Volker and Epp, Thomas and Jahnke, Thomas and Janßen, Martin and Siekmann, Angelika and Simanowsky, Ursula and Wuttke, Hans},
  title     = {Mathematik : Analytische Geometrie lineare Algebra ; Orientierungswissen Stochastik ; Handreichungen f{\"u}r den Unterricht ; Gymnasiale Oberstufe ; NRW},
  series = {Orientierungswissen Stoachstik},
  journal   = {Orientierungswissen Stoachstik},
  publisher = {Cornelsen},
  address   = {Berlin},
  isbn      = {3-464-57282-x},
  pages     = {456 S.},
  year      = {2004},
  language  = {de}
}
@article{QuaisserAlpers1998,
  author    = {Quaisser, Erhard and Alpers, Karsten},
  title     = {Lattices in the Pseudoeuclidean plane},
  year      = {1998},
  language  = {en}
}
@book{JankeWuttkeAlpersetal.2005,
  author    = {Janke, Thomas and Wuttke, Hans and Alpers, Karsten and Jahnke, Thomas and Janßen, Martin and Siekmann, Angelika and Simanowsky, Ursula},
  title     = {Fokus Mathematik ; Analytische Geometrie Lineare Algebra ; Gymnasiale Oberstufe ; Baden-W{\"u}rttemberg},
  editor    = {Janke, Thomas and Wuttke, Hans},
  publisher = {Cornelsen},
  address   = {Berlin},
  isbn      = {3-464-57340-0},
  pages     = {271 S.},
  year      = {2005},
  language  = {de}
}
@phdthesis{Alpers1995,
  author    = {Alpers, Karsten},
  title     = {Diskrete Bewegungsgruppen der pseudoeuklidischen Ebene},
  publisher = {Univ.},
  address   = {Potsdam},
  pages     = {II, 107 S.},
  year      = {1995},
  language  = {de}
}