APA (7th ed.) Citation

Milne, A. A., & Robinson, C. (2009). Once on a Time. Project Gutenberg.

Chicago Style (17th ed.) Citation

Milne, A. A., and Charles Robinson. Once on a Time. Project Gutenberg, 2009.

MLA (9th ed.) Citation

Milne, A. A., and Charles Robinson. Once on a Time. Project Gutenberg, 2009.

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