@article{Pur:71b,
  journal = {Studia Univ. Babe\c s-Bolyai, Ser. Math.-Phys.},
  title = {Sur un theoreme de Poincar\'{e}},
  author = {Purdea, Ioan},
  year = 1971,
  pages = {9--11},
  number = {2},
}