1. Advisory Committee on Mathematics in Education (ACME). (2002). Continuing professional development of teachers of mathematics: Advisory committee on mathematics in education. Retrieved from http://tinyurl.com/3u9pcmm
2. American Federation of Teachers (AFT). (2000). Distance education: Guidelines for good practice. Washington, DC: American Federation of Teachers. Retrieved from http://www.aft.org/pubs-reports/higher_ed/distance.pdf
3. Assessing teaching presence in a computer conferencing context.;T.Anderson;Journal of Asynchronous Learning Networks,2001