APA (7th ed.) Citation

Butts, E. R., & Schwartz, J. R. (2001). Carl Sagan. Lerner Publications.

Chicago Style (17th ed.) Citation

Butts, Ellen R., and Joyce R. Schwartz. Carl Sagan. Minneapolis: Lerner Publications, 2001.

MLA (9th ed.) Citation

Butts, Ellen R., and Joyce R. Schwartz. Carl Sagan. Lerner Publications, 2001.

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