@incollection{Pittner2009,
  author    = {Karin Pittner},
  title     = {Freie Relativs{\"a}tze und die Kasushierarchie},
  url       = {http://homepage.ruhr-uni-bochum.de/Karin.Pittner/LK90DRU_2.pdf},
  year      = {2009},
}