Srivastava, J. N.; Ghosh, S. - In: Statistics & Probability Letters 26 (1996) 1, pp. 51-60
The condition of proportional frequencies for main-effect plans is stated in Addelman (1962, 1963). The condition of equal frequencies is given in Rao (1946, 1947, 1973) and also in Plackett (1946) as a necessary and sufficient condition for orthogonality of the main-effect plans. The condition...
