Rao, B. Subba
Agro Botanical Publishers, 1992
Buku Referensi
Allaby, Michael, editor
Oxford University Press, 1992
Buku Referensi
Wilson, Carl L., author
Holt, Rinehart and Winston, 1962
Buku Teks
Neushul, Michael, author
Hamilton, 1974
Buku Teks
Dawes, Clinton J.
"New York: John Wiley & Sons, 1981",
Buku Teks