1. College of Mathematics, Inner Mongolia University for Nationalities, Tongliao, Inner Mongolia, China + School of Mathematical Sciences, Tianjin Polytechnic University, Tianjin, China + Institute of Mathematics, Henan Polytechnic University, Jiaozuo, Henan
2. Department of Mathematics, College of Arts and Science, Prince Sattam bin Abdulaziz University, Wadi Al dawaser, Saudi Arabia