1. College of Mathematics and Statistics, Chongqing Three Gorges University, Wanzhou 404120, Chongqing, China
2. Huji Senior Middle School Zhong Xiang, Zhongxiang 431911, Hubei, China
3. Guangzhou Huangpu District (Development Zone) Taxation Bureau, Guangdong Provincial Tax Service, State Taxation Administration, Guangzhou 510760, Guangdong, China