APA (7th ed.) Citation

Helm, A. T. (1931). Desert cacti and their spiny neighbors. Helm's Desert Publications.

Chicago Style (17th ed.) Citation

Helm, A. Truman. Desert Cacti and Their Spiny Neighbors. Phoenix, Ariz.: Helm's Desert Publications, 1931.

MLA (9th ed.) Citation

Helm, A. Truman. Desert Cacti and Their Spiny Neighbors. Helm's Desert Publications, 1931.

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