@article{SaloPetzschmannSpahnetal.1999,
  author    = {Salo, H. and Petzschmann, Olaf and Spahn, Frank and Schmidt, J{\"u}rgen},
  title     = {Vertical distribution of temperature and density in a planetary ring},
  year      = {1999},
  language  = {en}
}
@article{SpahnSchmidtPetzschmannetal.2000,
  author    = {Spahn, Frank and Schmidt, J{\"u}rgen and Petzschmann, Olaf and Salo, H.},
  title     = {Stability analysis of a Keplarian disk of granular grains : influence of thermal diffusion},
  year      = {2000},
  language  = {en}
}
@article{SchwarzKurthsSpahnetal.1998,
  author    = {Schwarz, Udo and Kurths, J{\"u}rgen and Spahn, Frank and Petzschmann, Olaf},
  title     = {Reply on the comment of "Clustering of granular assemblies with temperature dependent restitution and under differential rotation"},
  year      = {1998},
  language  = {en}
}
@phdthesis{Petzschmann1999,
  author    = {Petzschmann, Olaf},
  title     = {L{\"a}ngenskalen granularer Cluster},
  address   = {Potsdam},
  pages     = {99 S. : graph. Darst.},
  year      = {1999},
  language  = {de}
}
@article{SchwarzSpahnGrebogietal.1999,
  author    = {Schwarz, Udo and Spahn, Frank and Grebogi, Celso and Kurths, J{\"u}rgen and Petzschmann, Olaf},
  title     = {Length scales of clustering in granular gases},
  year      = {1999},
  language  = {en}
}
@article{PetzschmannThiessenhusenSpahnetal.1998,
  author    = {Petzschmann, Olaf and Thiessenhusen, Kai-Uwe and Spahn, Frank and Schmidt, J{\"u}rgen},
  title     = {Inelastic collisions in planetary rings : thickness and satellite-induced structures},
  isbn      = {0-7923-5102-9},
  year      = {1998},
  language  = {en}
}
@article{SpahnKatzorkePetzschmannetal.1997,
  author    = {Spahn, Frank and Katzorke, Ines and Petzschmann, Olaf and Schwarz, Udo and Kurths, J{\"u}rgen},
  title     = {Cluster instabiliy of granular assemblies},
  year      = {1997},
  language  = {en}
}
@article{SpahnPetzschmannSchmidtetal.2001,
  author    = {Spahn, Frank and Petzschmann, Olaf and Schmidt, J{\"u}rgen and Sremcevic, Miodrag and Hertzsch, Jan-Martin},
  title     = {About the viscosity of granular gases : the force-free case versus granular gases under Keplarian differential rotation},
  isbn      = {3-540-41458-4},
  year      = {2001},
  language  = {en}
}