Hirschfeld, Al. "Any Drawing on the Website". Al Hirschfeld.com. Margo Feiden Galleries Ltd. Archived from the original on May 4, 2013. Retrieved April 25, 2013.
Hirschfeld, Al. "Any Drawing on the Website". Al Hirschfeld.com. Margo Feiden Galleries Ltd. Archived from the original on May 4, 2013. Retrieved April 25, 2013.
This practice has given rise to the term "nina", used by crossword puzzle writers and fans to refer to "a hidden message revealed in the completed grid of a crossword".