Gibson, Chère Campbell, and Arlys O. Graff. 1992. “Impact of Adults’ Preferred Learning Styles and Perception of Barriers on Completion of External Baccalaureate Degree Programs”. International Journal of E-Learning & Distance Education Revue Internationale Du E-Learning Et La Formation à Distance 7 (1):39-51. https://ijede.ca/index.php/jde/article/view/413.