Most people are familiar with the dictum that one should only eat oysters in months containing the letter R, even though refrigeration has made this caution unnecessary. The letter R is contained in eight consecutive months, September through April, but absent from the remainder, May through August.
Eckler, A, Ross
"Renaming the Months,"
Word Ways: Vol. 18
, Article 16.
Available at: http://digitalcommons.butler.edu/wordways/vol18/iss3/16