Vincent, Nicholas, Isaac Johnson, Patrick Sheehan, and Brent Hecht. “Measuring the Importance of User-Generated Content to Search Engines”. Proceedings of the International AAAI Conference on Web and Social Media 13, no. 01 (July 6, 2019): 505-516. Accessed July 6, 2020. https://www.aaai.org/ojs/index.php/ICWSM/article/view/3248.