@article{PurBot:97,
  journal = {Studia Univ. Babe\c s-Bolyai, Ser. Mathematica},
  volume = {42},
  title = {Hereditary predicates},
  author = {Purdea, Ioan and Both, Nicolae},
  year = 1997,
  pages = {1--6},
  number = {1},
}