Martin, J. H., & Leonard, W. H. (1949). Principles of field crop production. Macmillan.
Lua i Stíl Chicago (17ú heag.)Martin, John H., agus Warren H. Leonard. Principles of Field Crop Production. New York: Macmillan, 1949.
Lua MLA (9ú heag.)Martin, John H., agus Warren H. Leonard. Principles of Field Crop Production. Macmillan, 1949.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.