@inproceedings{ZeldesLuedelingHirschmann2009,
  author    = {Amir Zeldes and Anke L{\"u}deling and Hagen Hirschmann},
  title     = {What's hard? : Quantitative evidence for difficult constructions in German learner data},
  booktitle = {Quantitative Investigations in Theoretical Linguistics 3 : QITL-3. - Helsinki, Finnland: 2008},
  url       = {http://www.ling.helsinki.fi/sky/tapahtumat/qitl/Presentations/Zeldes_et_al.ppt},
  year      = {2009},
}