@book{YagdjianGalstian2007,
  author    = {Yagdjian, Karen and Galstian, Anahit},
  title     = {Fundamental solutions for Wave Equation in de Sitter Model of Universe},
  series = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik, Arbeitsgruppe Partiell},
  journal   = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik, Arbeitsgruppe Partiell},
  publisher = {Univ.},
  address   = {Potsdam},
  issn      = {1437-739X},
  pages     = {36 S.},
  year      = {2007},
  language  = {en}
}
@book{GalstianYagdjian1997,
  author    = {Galstian, Anahit and Yagdjian, Karen},
  title     = {Exponential function of pseudo-differential operators},
  series = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik},
  volume    = {1997, 13},
  journal   = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik},
  publisher = {Univ.},
  address   = {Potsdam},
  pages     = {30 S.},
  year      = {1997},
  language  = {en}
}
@book{Galstian2001,
  author    = {Galstian, Anahit},
  title     = {Lp - Lq decay estimates for the equation with exponentionally growing coefficient},
  series = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik, Arbeitsgruppe Partiell},
  journal   = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik, Arbeitsgruppe Partiell},
  publisher = {Univ.},
  address   = {Potsdam},
  issn      = {1437-739X},
  pages     = {23 S.},
  year      = {2001},
  language  = {en}
}
@unpublished{Galstian2001,
  author    = {Galstian, Anahit},
  title     = {Lp - Lq decay estimates for the equation with exponentially growing coefficient},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-26079},
  year      = {2001},
  abstract  = {Contents: 1 Introduction 1 Representation formulas 2 Consideration in the pseudodifferential zone: e up(t) |ξ| ≤ 1 3 Consideration in he hyperbolic zone: e up(t) |ξ| ≥ 1},
  language  = {en}
}
@unpublished{GalstianYagdjian1997,
  author    = {Galstian, Anahit and Yagdjian, Karen},
  title     = {Exponential function of pseudo-differential operators},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-24982},
  year      = {1997},
  abstract  = {The paper is devoted to the construction of the exponential function of a matrix pseudo-differential operator which do not satisfy any of the known theorems (see, Sec.8 Ch.VIII and Sec.2 Ch.XI of [17]). The applications to the construction of the fundamental solution for the Cauchy problem for the hyperbolic operators with the characteristics of variable multiplicity are given, too.},
  language  = {en}
}
@unpublished{YagdjianGalstian2007,
  author    = {Yagdjian, Karen and Galstian, Anahit},
  title     = {Fundamental solutions for wave equation in de Sitter model of universe},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-30271},
  year      = {2007},
  abstract  = {In this article we construct the fundamental solutions for the wave equation arising in the de Sitter model of the universe. We use the fundamental solutions to represent solutions of the Cauchy problem and to prove the Lp - Lq-decay estimates for the solutions of the equation with and without a source term.},
  language  = {en}
}