@book{Baumgaertel1997,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {{\"U}ber Superauswahlstrukturen und deren Eichgruppen},
  series = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik},
  volume    = {1997, 06},
  journal   = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik},
  publisher = {Univ.},
  address   = {Potsdam},
  pages     = {13 Bl.},
  year      = {1997},
  language  = {de}
}
@book{Baumgaertel1997,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {Betrachtungen zur kulturellen Dimension der Mathematik},
  series = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik},
  volume    = {1997, 15},
  journal   = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik},
  publisher = {Univ.},
  address   = {Potsdam},
  pages     = {17 S.},
  year      = {1997},
  language  = {de}
}
@article{Baumgaertel1997,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {A modified approach to the Doplicher-Roberts theorem on the construction of the field algebra and the symmetry group in superselection theory},
  year      = {1997},
  language  = {en}
}
@article{BaumgaertelLledo1997,
  author    = {Baumg{\"a}rtel, Hellmut and Lled{\´o}, Fernando},
  title     = {Some results on superselection structures for C*-algebras with nontrivial center},
  isbn      = {981-02-3984-X},
  year      = {1997},
  language  = {en}
}
@article{BaumgaertelLledo1997,
  author    = {Baumg{\"a}rtel, Hellmut and Lled{\´o}, Fernando},
  title     = {Superselection structures for C*-algebras with nontrivial center},
  year      = {1997},
  language  = {en}
}