APA (7th ed.) Citation

Ridgely, R. S. Hummingbirds of Ecuador: Field guide.

Chicago Style (17th ed.) Citation

Ridgely, Robert S. Hummingbirds of Ecuador: Field Guide.

MLA (8th ed.) Citation

Ridgely, Robert S. Hummingbirds of Ecuador: Field Guide.

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