Hew, Khe Foon, et al. “Understanding Student Engagement in Large-Scale Open Online Courses: A Machine Learning Facilitated Analysis of Student’s Reflections in 18 Highly Rated MOOCs”. The International Review of Research in Open and Distributed Learning, vol. 19, no. 3, July 2018, doi:10.19173/irrodl.v19i3.3596.