Engelken, R., Engelken, R., & Slattery, P. (1981). The art of natural farming & gardening. Barrington Hall Press.
Chicago Style (17. basım) AtıfEngelken, Ralph, Rita Engelken, ve Pat Slattery. The Art of Natural Farming & Gardening. Greeley, Iowa: Barrington Hall Press, 1981.
MLA (8th ed.) AtıfEngelken, Ralph, et al. The Art of Natural Farming & Gardening. Barrington Hall Press, 1981.
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