Naeem Ahmed, Tariq Shah, Wakeel Ahmad, and S.M. Adnan Shah. “A Comprehensive Survey on Sentiment Analysis Using Machine Learning Techniques”. University of Sindh Journal of Information and Communication Technology, vol. 4, no. 4, Dec. 2020, pp. 227-33, https://sujo.usindh.edu.pk/index.php/USJICT/article/view/3297.