1. School of Mathematics and Statistics, Guizhou University of Finance and Economics, Guiyang 550025, China
2. Guizhou Key Laboratory of Economics System Simulation, Guizhou University of Finance and Economics, Guiyang 550025, China
3. School of Mathematics and Statistics, Henan University of Science and Technology, Luoyang 471023, China
4. Library, Guizhou University of Finance and Economics, Guiyang 550025, China