| 1 | Anderson, T. (2004). Theory and practice of online learning. Athabasca University. |
| 2 | Barbour, M. K., & Stewart, R. (2008). A snapshot state of the nation study: K-12 online learning in Canada. North American Council for Online Learning. |
| 3 | Dabbagh, N., & Bannan-Ritland, B. (2005). Online learning: Concepts, strategies, and application. Upper Saddle River NJ: Prentice Hall, Inc. |