@book{JonasLanger1994,
  author    = {Jonas, Peter and Langer, Heinz},
  title     = {Selfadjoint extensions of a closed linear realtion of defect one in a Krein space. Universit{\"a}t Potsdam, Fachbereich Mathematik},
  series = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik},
  volume    = {1994, 17},
  journal   = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik},
  publisher = {Univ.},
  address   = {Potsdam},
  pages     = {35 Bl.},
  year      = {1994},
  language  = {de}
}
@book{Jonas1997,
  author    = {Jonas, Peter},
  title     = {Riggings and relatively form bounded perturbations of nonnegative operators in Krein spaces},
  series = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik},
  volume    = {1997, 37},
  journal   = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik},
  publisher = {Univ.},
  address   = {Potsdam},
  pages     = {15 S.},
  year      = {1997},
  language  = {en}
}
@book{Jonas1997,
  author    = {Jonas, Peter},
  title     = {Operator representations of definitizable functions},
  series = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik},
  volume    = {1997, 34},
  journal   = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik},
  publisher = {Univ.},
  address   = {Potsdam},
  pages     = {29 S.},
  year      = {1997},
  language  = {en}
}