Author(s): |
Shuangcheng Li, School of Mathematics and Statistics, Hebei University of Economics And Business, Shijiazhuang, China, 050061 Min Feng, Shijiazhuang Vocational and technical colleges of Posts and Telecommunications, Shijiazhuang, China, 050031 Ping Wan, School of Mathematics and Statistics, Hebei University of Economics And Business, Shijiazhuang, China, 050061 |