Unesco, 1981
Buku Teks
Kay, Robert, author
Routledge, 2005
Buku Teks
by Lincoln D. Cathers...[et al.]; editor, J.F. Peel Brahtz
John Wiley, 1972
Buku Teks
Anderson, Robert S. (Robert Stewart), 1952-
Cambridge University Press, 2010
Buku Teks
Riri Oktaviani, author
Fakultas Ilmu Sosial dan Ilmu Politik Universitas Indonesia, 2013
UI - Tesis (Membership)