APA (7e ed.) Bronvermelding

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

Chicago (17e ed.) Bronvermelding

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

MLA (8e ed.) Bronvermelding

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