Nelson, Lowry, author
American Book, 1955
Buku Teks
Chambers, Robert, 1932-, author
LP3ES, 1988
Buku Teks
Loomis, Charles P., author
Prentice-Hall, 1957
Buku Teks
Asian and Pacific Development Administration Centre, 1980
Buku Teks
edited by Michael Pacione
Routledge, 2014
Buku Teks