APA (7th ed.) Citation

Adams, S. W., Petersham, M. F., & Petersham, M. (2008). Five Little Friends. Project Gutenberg.

Chicago Style (17th ed.) Citation

Adams, Sherred Willcox, Maud Fuller Petersham, and Miska Petersham. Five Little Friends. Project Gutenberg, 2008.

MLA (9th ed.) Citation

Adams, Sherred Willcox, et al. Five Little Friends. Project Gutenberg, 2008.

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