8Miller, G.A.(1956).The Magical Number Seven, Plus or Minus Two:Some Limits on Our Capacity for Processing Information[J].The Psychological Review,63:81-97.
9Hillman,D.C.A.,Willis, D.J.,&Gunawardcna,C.N.(1994). Learner-lnterface Interaction in Distance Education: An Extension of Contemporary Models and Strategies for Practitioners[J].The American Journal of Distance Education,8(2):30-42.
10Laurillard, D.(2001).Rethinking University Teaching: A Conversational Framework for the Effective Use of Learning Technologies(2nd edition)[M].London:Routledge.