APA (7th ed.) Citation

Higgins, R. T., & Willems, M. (2020). What about worms!? (First edition.). Hyperion Books for Children.

Chicago Style (17th ed.) Citation

Higgins, Ryan T., and Mo Willems. What About Worms!? First edition. New York: Hyperion Books for Children, 2020.

MLA (8th ed.) Citation

Higgins, Ryan T., and Mo Willems. What About Worms!? First edition. Hyperion Books for Children, 2020.

Warning: These citations may not always be 100% accurate.