Tian, Y., and R. Chunara. “Quasi-Experimental Designs for Assessing Response on Social Media to Policy Changes”. Proceedings of the International AAAI Conference on Web and Social Media, vol. 14, no. 1, May 2020, pp. 671-82, https://ojs.aaai.org/index.php/ICWSM/article/view/7333.