Hughes, H. D. M., & Metcalfe, D. S. (1972). Crop production (3d ed.). Macmillan.
Lua i Stíl Chicago (17ú heag.)Hughes, Harold De Mott, agus Darrel S. Metcalfe. Crop Production. 3d ed. New York: Macmillan, 1972.
Lua MLA (8ú heag.)Hughes, Harold De Mott, agus Darrel S. Metcalfe. Crop Production. 3d ed. Macmillan, 1972.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.