M. Rao, K. Swamy, K.Anithasheela, and B. Mohan. International Journal of Computer Science, Engineering and Information Technology (IJCSEIT), 2 (1):
67-74(February 2012)
M. Feuer, L. Towne, and R. Shavelson. Educational Researcher, 31 (8):
4(2002)“For example, when well-specified causal hypotheses can be formulated and randomization to treatment and control conditions is ethical and feasible, a randomized experiment is the best method for estimating effects” p. 8.