Author/Authors :
T. Allahviranloo، T. Allahviranloo نويسنده T. Allahviranloo, T. Allahviranloo , P. Salehi، P. Salehi نويسنده Department of mathematics, Hamedan Branch, Islamic Azad University, Hamedan, Iran P. Salehi, P. Salehi , M. Nejatiyan، M. Nejatiyan نويسنده Department of mathematics, Science and Research Branch, Islamic Azad University, Tehran, Iran M. Nejatiyan, M. Nejatiyan