Eberstadt, Nick Ed.)
Praeger Publishers, 1981
Buku Teks
Chambers, Robert, 1932-, author
Longman, 1983
Buku Teks
Carman, John S.
Pergamon Press, 1979
Buku Teks
Coombs, Philip H., author
Johns Hopkins University Press, 1974
Buku Teks
Coombs, Philip H., author
John Hopkins University Press, 1988
Buku Teks