ZHANG, Kai-guang, Hong-ling MENG, Ming-ting BA, and Yan-min SUN. “Correlation Analysis of Main Pollutant Concentration-A Case Study of Zhengzhou”. Journal of Progressive Research in Mathematics 15, no. 2 (August 21, 2019): 2632-2640. Accessed December 21, 2024. http://scitecresearch.com/journals/index.php/jprm/article/view/1751.