Richardson, Jennifer C, Adrie A. Koehler, Erin D. Besser, Secil Caskurlu, JiEun Lim, and Chad M. Mueller. “Conceptualizing and Investigating Instructor Presence in Online Learning Environments”. The International Review of Research in Open and Distributed Learning 16, no. 3 (June 19, 2015). Accessed April 26, 2024. https://www.irrodl.org/index.php/irrodl/article/view/2123.