Thampan, Palakasseril Kumaran
Oxford & IBH Publishing Co., 1981
Buku Referensi
Anderson, J. M., editor
CAB International, 1993
Buku Referensi
edited by W.A. Paton
Ronald Press, 1955
Buku Teks
editor, Harry Helms [and others]
McGraw-Hill, 1983
Buku Referensi
William J. Hardcastle, John Laver, Fiona E. Gibbon, editor
Wiley-Blackweell, 2013
Buku Teks