Long, Norman
Tavistock Publication, 1980
Buku Teks
Nelson, Lowry
American Book, 1955
Buku Teks
edited by Barbara Ching and Gerald W. Creed
Routledge , 1997
Buku Teks
Loomis, Charles P.
Prentice-Hall, 1957
Buku Teks
Chitambar, J. B.
Wiley Eastern Limited, 1973
Buku Teks