In "How Many Words Support a Square?" in the May 1992 Word Ways, I definied the "support" of a word square to be the number of words required, on the average, to form a single word square, and showed that it could be experimentally calculated by means of the scaling formula.
Eckler, A. Ross
"Word-Square Support: Part 1,"
Word Ways: Vol. 26
, Article 15.
Available at: http://digitalcommons.butler.edu/wordways/vol26/iss3/15