@article{Perlmutter2009,
  author    = {David M. Perlmutter},
  title     = {Multiattachment and the unaccusative hypothesis : the perfect auxiliary in Italian},
  journal   = {Probus : an international journal of Latin and Romance linguistics},
  volume    = {1},
  number    = {1},
  pages     = {63 -- 119},
  year      = {2009},
}