Cita APA (7a ed.)

Numeroff, L. J., & McPhail, D. (2006). When sheep sleep. Abrams Books for Young Readers.

Cita Chicago Style (17a ed.)

Numeroff, Laura Joffe, y David McPhail. When Sheep Sleep. New York: Abrams Books for Young Readers, 2006.

Cita MLA (8a ed.)

Numeroff, Laura Joffe, y David McPhail. When Sheep Sleep. Abrams Books for Young Readers, 2006.