@incollection{CorPur:86,
  title = {On the category of the $n$-ary monoid extensions},
  year = 1986,
  booktitle = {Proc. of the Conference on Algebra},
  pages = {71--73},
  publisher = {Babe\c s-Bolyai University},
  olume = {Preprint no. 9},
  author = {Corovei, Ilie and Purdea, Ioan},
  series = {Faculty of Mathematics Research Seminaries},
}