About this article
Published Online: Mar 25, 2015
Page range: 171 - 182
Received: Oct 03, 2014
Accepted: Dec 29, 2014
DOI: https://doi.org/10.2478/awutm-2014-0018
Keywords
© Annals of West University of Timisoara - Mathematics
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.
Rezaei, Akbar
Saeid, Arsham Borumand