This last article in the series deals with 4-letter words, which tend to be the most common in use. In the top 87,000 words, there are 5356 of four letters, including 462 reversible words and 24 palindromic words. From these, it was possible to make 5261 squares.
"All-Diagonal 4-Squares With Common Words,"
Word Ways: Vol. 39
, Article 13.
Available at: http://digitalcommons.butler.edu/wordways/vol39/iss4/13