BirdLife International, 2003
Multimedia
Stefferud, Alfred, editor
United States. Government Printing Office, 1966
Buku Referensi
Walters, Martin
Miles Kelly, 2000
Buku Referensi
Kothari, Ashish
Universities Press, 2007
Buku Teks
McClure, H. Elliott (Howe Elliott), 1910-, author
SEATO, 1974
Buku Teks