%0 Journal Article
%A T. A. Grigoryan
%A E. V. Lipacheva
%A V. H. Tepoyan
%T On $\pi$-extensions of the semigroup $\mathbb{Z}_+$
%J Proceedings of the Yerevan State University. Physical and mathematical sciences
%D 2013
%P 3-5
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/UZERU_2013_1_a0/
%G en
%F UZERU_2013_1_a0