پديدآورندگان :
Khanehgir Mahnaz khanehgir@mshdiau.ac.ir Department of Mathematics, Mashhad Branch,
Islamic Azad University, Mashhad, Iran;
, Gholamian Nayereh nayereh1183@yahoo.com Department of Mathematics, Shirvan Branch,
Islamic Azad University, Shirvan, Iran;