APA (7th ed.) Citation

Foster, S. (1991). Echinacea: Nature's immune enhancer. Healing Arts Press.

Chicago Style (17th ed.) Citation

Foster, Steven. Echinacea: Nature's Immune Enhancer. Vermont: Healing Arts Press, 1991.

MLA (9th ed.) Citation

Foster, Steven. Echinacea: Nature's Immune Enhancer. Healing Arts Press, 1991.