APA (7th ed.) Citation

Greengo, J. (2019). 50 things photographers need to know about focus (1st edition.). Rocky Nook.

Chicago Style (17th ed.) Citation

Greengo, John. 50 Things Photographers Need to Know About Focus. 1st edition. San Rafael, CA: Rocky Nook, 2019.

MLA (8th ed.) Citation

Greengo, John. 50 Things Photographers Need to Know About Focus. 1st edition. Rocky Nook, 2019.

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