Cita APA (7th ed.)

Engelken, R., Engelken, R., & Slattery, P. (1981). The art of natural farming & gardening. Barrington Hall Press.

Cita Chicago (17th ed.)

Engelken, Ralph, Rita Engelken, i Pat Slattery. The Art of Natural Farming & Gardening. Greeley, Iowa: Barrington Hall Press, 1981.

Cita MLA (8th ed.)

Engelken, Ralph, et al. The Art of Natural Farming & Gardening. Barrington Hall Press, 1981.