5Wanta W, Roy M J. Memory Decay and The Agenda- setting Effect: An Examination of Three New Media[R].The Annual Meeting of the Association for Education in Tnnrnalism and Mass Communication, Washington DC,1995.
6Funkhouser G R. The issue of the sixties: An exploratory study in the dynamics of public opinion[J].Public Opinion Quarterly,1973,37(1):62- 75.
