APA (7th ed.) Citation

Duffield, J. W. (2006). Bert Wilson in the Rockies. Project Gutenberg.

Chicago Style (17th ed.) Citation

Duffield, J. W. Bert Wilson in the Rockies. Project Gutenberg, 2006.

MLA (9th ed.) Citation

Duffield, J. W. Bert Wilson in the Rockies. Project Gutenberg, 2006.

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