APA (7th ed.) Citation

Putnam, N. W. (2013). It Pays to Smile. Project Gutenberg.

Chicago Style (17th ed.) Citation

Putnam, Nina Wilcox. It Pays to Smile. Project Gutenberg, 2013.

MLA (9th ed.) Citation

Putnam, Nina Wilcox. It Pays to Smile. Project Gutenberg, 2013.

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