Kirkwood, Adrian. “Instructional Technology: A Systematic Approach to Education - F.G. Knirk, K.L. Gustafson”. International Journal of E-Learning & Distance Education Revue Internationale Du E-Learning Et La Formation à Distance, vol. 2, no. 1, Apr. 1987, pp. 94-96, https://ijede.ca/index.php/jde/article/view/571.