@article{Vicente2016,
  author    = {Luis Vicente},
  title     = {Free versus bound variables and the taxonomy of gaps},
  journal   = {Natural language semantics : an international journal of semantics and its interfaces in grammar},
  volume    = {24},
  pages     = {203 -- 245},
  doi       = {10.1007/s11050-016-9123-6},
  year      = {2016},
}