Yertle the Tertle

Yertle the Tertle is a children's book that is, according to Lisa Simpson, "possibly the greatest book ever written on the subject of turtle-stacking." Chief Wiggum agreed with this assessment.

Behind the Laughter
Yertle the Turtle is a real book by Dr. Seuss, but the word "turtle" is actually spelled the correct way in contrast to the incorrect spelling used on The Simpsons.