@article{Pur:75a,
  journal = {Studia Univ. Babe\c s-Bolyai, Ser. Math.-Phys.},
  title = {Les anneaux de type $(m,n)$ I.},
  author = {Purdea, Ioan},
  year = 1975,
  pages = {3--11},
  number = {1},
}