R.K.Atkinson,, S.H.Derry,, A.Renkl,, & D.Wrotham, (2000). Learning from examples: Instructional principles from the worked examples research. Review of Educational Research, 70(2) 181–214.
R.K.Atkinson,, A.Renkl,, & M.M.Merrill, (2003). Transition from studying examples to solving problems: Effects of self-explanation prompts and fading worked out steps. Journal of Educational Psychology, 95(4), 774–783.
R.C.Clark,, & C.Lyons, (2004). Graphics for learning. San Francisco: CA: Pfeiffer.
S.Tindall-Ford,, P.Chandler,, & J.Sweller, (1997). When two sensory modes are better than one. Journal of Experimental Psychology: Applied, 3(4), 257–287.