Cascaval, Radu C.; Fogler, Kethera A.; Abrams, Gene D.; Durham, Robert L. (December 2008). "Evaluating the Benefits of Providing Archived Online Lectures to In-Class Math Students". Journal of Asynchronous Learning Networks. 12: 61–70. ISSN 1939-5256. Retrieved September 24, 2016. http://eric.ed.gov/?id=EJ837515
Cascaval, Radu C.; Fogler, Kethera A.; Abrams, Gene D.; Durham, Robert L. (December 2008). "Evaluating the Benefits of Providing Archived Online Lectures to In-Class Math Students". Journal of Asynchronous Learning Networks. 12: 61–70. ISSN 1939-5256. Retrieved September 24, 2016. http://eric.ed.gov/?id=EJ837515