7Moore, M.. Three Types of Interaction[J]. American Journal of Distance Education, 1989, 3(2) : 1-6.
8Hillman, D.C.A., Willis, D.J., Gunawardena, C.N.. Learner-Interface Interaction in Distance Education: An Extension of Contemporary Models and Strategies for Practitioners[J]. American Journal of Distance Education, 1994, 8(2) : 30-42.
9Waycott, J., Kukulska-Hulme,A.. Students" Experiences with PDAs for Reading Course Materials [J]. Personal and Ubiquitous Computing, 2003, 7(1) : 30-43.
10Sanchez,C.A., Goolsbee,J.Z.. Character Size and Reading to Remember from Small Displays[J]. Computers & Education, 2010, 55(3) : 1056-1062.