APA (7th ed.) Citation

Little, E. L. (1950). Southwestern trees: A guide to the native species of New Mexico and Arizona. U.S. Dept. of Agriculture.

Chicago Style (17th ed.) Citation

Little, Elbert L. Southwestern Trees: A Guide to the Native Species of New Mexico and Arizona. [Washington, D.C.]: U.S. Dept. of Agriculture, 1950.

MLA (9th ed.) Citation

Little, Elbert L. Southwestern Trees: A Guide to the Native Species of New Mexico and Arizona. U.S. Dept. of Agriculture, 1950.