@book{Pur:96,
  publisher = {Universitatea Babe\c s-Bolyai},
  address = {Cluj-Napoca},
  title = {Culegere de probleme de algebr\u a (Rela\c tii, func\c tii \c si
           algebre universale)},
  author = {Purdea, Ioan},
  year = {1996},
  pages = {67},
}