@article{Baumgaertel1995,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {Fourier transformation of Hilbert C*-systems, with compact groups, by their regular representation},
  year      = {1995},
  language  = {en}
}
@article{Baumgaertel1995,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {On Haag dual nets over compact spaces},
  year      = {1995},
  language  = {en}
}
@book{Baumgaertel1993,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {Some operatoralgebraic fundamentals of the algebraic quantum field theory},
  series = {Preprint / Universit{\"a}t Potsdam, Fachbereich Mathematik},
  volume    = {1993, 09},
  journal   = {Preprint / Universit{\"a}t Potsdam, Fachbereich Mathematik},
  publisher = {Univ.},
  address   = {Potsdam},
  pages     = {43 Bl.},
  year      = {1993},
  language  = {en}
}
@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{Baumgaertel2012,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {On a critical radiation density in the Friedmann equation},
  series = {Journal of mathematical physics},
  volume    = {53},
  journal   = {Journal of mathematical physics},
  number    = {12},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {0022-2488},
  doi       = {10.1063/1.4771668},
  pages     = {9},
  year      = {2012},
  abstract  = {The paper presents a classification of the basic types of admissible solutions of the general Friedmann equation with non-vanishing cosmological constant and for the case that radiation and matter do not couple. There are four distinct types. The classification uses first the discriminant of a polynomial of the third degree, closely related to the right hand side of the Friedmann equation. The decisive term is then a critical radiation density which can be calculated explicitly.},
  language  = {en}
}
@article{Baumgaertel2001,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {An Application of the DR-Duality Theory for Compact Groups to Endomorphism Categories of C*-Algebras with Nontrivial Center},
  year      = {2001},
  language  = {en}
}
@article{Baumgaertel2000,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {Dual actions on C*-algebras and Hilbert extensions},
  year      = {2000},
  language  = {en}
}
@article{Baumgaertel2000,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {On a theorem of Ashtekar and Lewandowski in the mathematical framework of canonical quantization in quantum gravity},
  year      = {2000},
  language  = {en}
}
@book{Baumgaertel1999,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {Cuntz algebras and superselection structures in Quantum Field Theory},
  series = {LQP Papers / Local Quantum Physics Crossroads},
  journal   = {LQP Papers / Local Quantum Physics Crossroads},
  publisher = {Univ.},
  address   = {G{\"o}ttingen},
  year      = {1999},
  language  = {en}
}
@article{Baumgaertel1999,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {On a theorem of Ashtekar and Lewandowski},
  isbn      = {981-023627-1},
  year      = {1999},
  language  = {en}
}