1. School of Mathematics and Statistics, Guizhou University of Finance and Economics, Guiyang, People’s Republic of China
2. Mathematical Science Research Center, Chongqing University of Technology, Chongqing, People’s Republic of China + School of Mathematics, Yunnan Normal University, Kunming, People’s Republic of China
3. School of Mathematics, Baoshan University, Baoshan, People’s Republic of China