Coffman, F. (1966). SPECIAL ENGLISH AGRICULTURE BOOK II: FIELD CROPS. Callier-Macmillan, limited.
Lua i Stíl Chicago (17ú heag.)Coffman, F.A. SPECIAL ENGLISH AGRICULTURE BOOK II: FIELD CROPS. Callier-Macmillan, limited, 1966.
Lua MLA (8ú heag.)Coffman, F.A. SPECIAL ENGLISH AGRICULTURE BOOK II: FIELD CROPS. Callier-Macmillan, limited, 1966.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.