Reprinted with permission from Homage to a Pied Puzzler, ed. by E. Pegg, Jr., A.H. Schoen and T. Rodgers, AK Peters 2009 (www.akpeters.com).
Farrell, Jeremiah and Friedhoffer, Robert
"The Logologicomathematical 7x7 Puzzle,"
Word Ways: Vol. 42
, Article 20.
Available at: http://digitalcommons.butler.edu/wordways/vol42/iss3/20