Kothari, Ashish M.
Universities Press, 2007
Buku Teks SO
Walters, Martin
Miles Kelly, 2000
Buku Referensi
by Rudolph L. Schreiber ... [and others]
Houghton Mifflin, 1989
Buku Teks SO
McClure, Howe Elliott, 1910-
Applied Scientific Research Corporation, [Date of publication not identified]
Buku Referensi
McClure, Howe Elliott, 1910-
SEATO, 1974
Buku Teks SO