@article{Pur:74,
  journal = {Studia Univ. Babe\c s-Bolyai, Ser. Math.-Phys.},
  title = {$\Omega$-semigroupes des fractions d'un $\Omega$-semigroupe},
  author = {Purdea, Ioan},
  year = 1974,
  pages = {16--18},
  number = {2},
}