APA (7th ed.) Citation

Marsh, C. D., & Clawson, A. B. (1921). The Mexican whorled milkweed (Asclepias mexicana as a poisonous plant. U.S. Dept. of Agriculture.

Chicago Style (17th ed.) Citation

Marsh, C. Dwight, and A. B. Clawson. The Mexican Whorled Milkweed (Asclepias Mexicana as a Poisonous Plant. Washington, D.C.: U.S. Dept. of Agriculture, 1921.

MLA (9th ed.) Citation

Marsh, C. Dwight, and A. B. Clawson. The Mexican Whorled Milkweed (Asclepias Mexicana as a Poisonous Plant. U.S. Dept. of Agriculture, 1921.