@book{HaenselNeumannHudel1993,
  author    = {H{\"a}nsel, Horst and Neumann, Werner and Hudel, Erich},
  title     = {Physik : Bd. 2 Elektrizit{\"a}t, Optik, Raum und Zeit},
  volume    = {2},
  publisher = {Spektrum Akad. Verl.},
  address   = {Heidelberg},
  isbn      = {3-86025-304-2},
  pages     = {799 S.},
  year      = {1993},
  language  = {de}
}
@book{HaenselNeumannHudel1995,
  author    = {H{\"a}nsel, Horst and Neumann, Werner and Hudel, Erich},
  title     = {Physik : Bd. 3 Atome, Atomkerne, Elementarteilchen},
  volume    = {3},
  publisher = {Spektrum Akad. Verl.},
  address   = {Heidelberg},
  isbn      = {3-86025-313-1},
  pages     = {742 S.},
  year      = {1995},
  language  = {de}
}