Song, Xiaoxiao, Tao Tao, Tao Tao, Qi Zhao, Lars Palm, Shaofa Nie, Hui Yuan, Vinod K. Diwan, and Biao Xu. “The Growth and Variation of Symptoms of Influenza-Like Illness: An Application of the Linear Growth Curve Model in Syndromic Surveillance in Rural China”. Online Journal of Public Health Informatics 6, no. 1 (March 9, 2014). Accessed January 20, 2022. https://ojphi.org/ojs/index.php/ojphi/article/view/5180.