@article{Graff2019,
  author    = {Graff, Thomas},
  title     = {Testdokument},
  series = {Pr{\"u}fungsdokument},
  journal   = {Pr{\"u}fungsdokument},
  pages     = {1 -- 5},
  year      = {2019},
  abstract  = {Dieser Artikel besch{\"a}ftigt sich mit einem Testdument.},
  language  = {de}
}
@techreport{DoeZufallFall2010,
  author    = {Doe, John and Zufall, Rainer and Fall, Klara},
  title     = {This is a pdf test document},
  series = {This is a parent title},
  journal   = {This is a parent title},
  year      = {2010},
  abstract  = {This is a pdf test document},
  subject      = {Informationssystem},
  language  = {en}
}
@article{DoeZufall2009,
  author    = {Doe, John and Zufall, Rainer},
  title     = {This is a xhtml test document},
  year      = {2009},
  abstract  = {This is a xhtml test document},
  subject      = {Informationssystem},
  language  = {en}
}
@phdthesis{DoeFall2009,
  author    = {Doe, John and Fall, Klara},
  title     = {This is a plain text test document},
  school      = {Foobar Universit{\"a}tsbibliothek},
  year      = {2009},
  abstract  = {This is a plain text test document},
  subject      = {Informationssystem},
  language  = {en}
}
@techreport{Doe2008,
  author    = {Doe, John},
  title     = {This is a postscript test document},
  year      = {2008},
  abstract  = {This is a postscript test document},
  subject      = {Informationssystem},
  language  = {en}
}
@article{Walruss2008,
  author    = {Walruss, Wally},
  title     = {What you always wanted to know about Opus and never dared to ask!},
  year      = {2008},
  language  = {en}
}
@article{Doe2008,
  author    = {Doe, John},
  title     = {This is an unpublished test document with \$LaTeX - Code\$ in it. For example, \(\sqrt{3x-1}+(1+x)^2\) is an squareroot.},
  year      = {2008},
  abstract  = {\[ \left( \sum_{k=1}^n a_k b_k \right)^2 \leq \left( \sum_{k=1}^n a_k^2 \right) \left( \sum_{k=1}^n b_k^2 \right) \]},
  language  = {en}
}