@Article{noKey,
  author = {Krause, Beate and Lerch, Hana and Hotho, Andreas and Roßnagel, Alexander and Stumme, Gerd},
  title  = {Datenschutz im Web 2.0 am Beispiel des sozialen Tagging-Systems BibSonomy},
  journal = {Informatik-Spektrum},
  year   = {2012},
  number = {1},
  url    = {http://dx.doi.org/10.1007/s00287-010-0485-8},
  doi = {10.1007/s00287-010-0485-8},
  const  = {\ text}
}
@Article{fenn2006managing,
  author = {Fenn, Jürgen},
  title  = {Managing citations and your bibliography with BibTeX},
  journal = {The PracTeX Journal},
  year   = {2006},
  number = {},
  url    = {},

  const  = {\ text}
}
@Book{knappen2004schnell,
  author = {Knappen, Jörg},
  title  = {Schnell ans Ziel mit LATEX 2e},

  year   = {2004},
  number = {},
  url    = {http://scans.hebis.de/HEBCGI/show.pl?12277978_toc.pdf},

  const  = {\ text}
}