Barrett, O. W. (1928). The tropical crops. The Macmillan Company.
Lua i Stíl Chicago (17ú heag.)Barrett, Otis Warren. The Tropical Crops. New York: The Macmillan Company, 1928.
Lua MLA (9ú heag.)Barrett, Otis Warren. The Tropical Crops. The Macmillan Company, 1928.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.