@article{LeuL:02a,
  journal = {Journal of Multiple-Valued Logic},
  volume = 8,
  title = {Canonical models and filtrations in three-valued propositional modal
           logic},
  author = {Leu\c stean, Lauren\c tiu},
  year = 2002,
  pages = {577--590},
  number = {1--2},
}