2Gagne, R. M, (1985). The Conditions of Learning and Theory of Instruction ( 4th ed, ), New York:Holt ,Rinehart,and Winston.
3Gagne,R. M..Briggs,L, &.Wager,W. (1992).Principles of Instructional Design (4th ed. ). Fort Worth. TX: Harcourt Brace Jovanovich College Publishers.
4Hattie, J. , Biggs, J. , &Purdie, N. (1996),Effects of Learning Skills Interventions on Student Learning: A Meta- analysis. Review of Educational Research, 66(2), 99-136.
5Brown, J. S. and Duguid, P. ( 1993 ). Stolen Knowledge. Educational Technology', Vol. 33, No. 3,pp,.10-15.