APA (7th ed.) Citation

Snell, R. J. (2007). The Blue Envelope. Project Gutenberg.

Chicago Style (17th ed.) Citation

Snell, Roy J. The Blue Envelope. Project Gutenberg, 2007.

MLA (9th ed.) Citation

Snell, Roy J. The Blue Envelope. Project Gutenberg, 2007.

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