1. Trowbridge, J. R., and J. Rubinfeld, “Proceedings of the Fourth International Congress on Surface Active Substances”, Vol. 3, Gordon and Breach Science Publishers, New York, 1967, p. 221.
2. Cochran, W. A., and G. M. Cox, “Experimental Design”, 2nd Edition, John Wiley & Sons, Inc., New York, 1957, Ch. 5.
3. Winer, B. J., “Statistical Principles in Experimental Design”, McGraw-Hill Book Co., New York, 1962, p. 77–89.