8Bhattacharaya, M. A study of asynchronous and synchronous discussion on Cognitive maps in a distributed learning environment [DB/OL]. http://www.eric.ed.gov /ERICDocs/ data/ericdocs2sq1/ content_storage_ 01/0000019b/80/16/c2/80.pdf.
9Davie, L.Facilitatipn of adult learning through computer conferencing[A], in proceeding of the Second Guelph Symposium on Computer Conferencing[C].Guetph, Ontario: University of Guelph, 1987.11-22.
10Cooper, M.M.&C.L.Selfe. Computer conferences and learning: Authority,Resistance, and internally persuasiw discourse[J]. College English, 1990.52(8):847 -869.
