1. Allen, I. E., & Seaman, J. (2013). Changing course: Ten years of tracking online education in the United States. ERIC.
2. Angelo, T. A. (1993). A Teacher’s Dozen: Fourteen general research-based principles for improving higher learning in our classrooms. American Association for Higher Learning Bulletin, 45(6), 3–13.
3. Åström, E. (2008). E-Learning quality: Aspects and criteria for evaluation of e-Learning in higher education. Retrieved from http://www.eadtu.nl/e-xcellencelabel/files/0811R.pdf .
4. Azeiteiro, U. M., Bacelar-Nicolau, P., Caetano, F. J. P., & Caeiro, S. (2015). Education for sustainable development through e-learning in higher education: Experiences from Portugal. Journal of Cleaner Production, 106, 308–319.
5. Bacsich, P. (2009). Benchmarking e-learning in UK Universities—the methodologies. In T. Mayes, D. Morrison, H. Mellar, P. Bullen, & M. Oliver (Eds.), Transforming higher education through technology—enhanced learning (pp. 90–106). The Higher Education Academy.