APA (7th ed.) Citation

Whitman, W., & Long, L. (2004). When I heard the learn'd astronomer. Simon & Schuster Books for Young Readers.

Chicago Style (17th ed.) Citation

Whitman, Walt, and Loren Long. When I Heard the Learn'd Astronomer. New York: Simon & Schuster Books for Young Readers, 2004.

MLA (9th ed.) Citation

Whitman, Walt, and Loren Long. When I Heard the Learn'd Astronomer. Simon & Schuster Books for Young Readers, 2004.