@article{Zeijlstra2009,
  author    = {Hedde Zeijlstra},
  title     = {Hard and soft conditions on the faculty of language},
  journal   = {Linguistics in Potsdam},
  series    = {constituting parametric variation},
  number    = {28},
  pages     = {9 -- 38},
  year      = {2009},
}