APA (7th ed.) Citation

Geisel, T. S. (1938). The 500 hats of Bartholomew Cubbins. Vanguard Press.

Chicago Style (17th ed.) Citation

Geisel, Theodor Seuss. The 500 Hats of Bartholomew Cubbins. New York: Vanguard Press, 1938.

MLA (9th ed.) Citation

Geisel, Theodor Seuss. The 500 Hats of Bartholomew Cubbins. Vanguard Press, 1938.