Benham, Frederic, author
Oxford University Press, 1962
Buku Teks
Todaro, Michael P., author
Bumi Aksara, 1995
Buku Teks
Howe, James W., author
Praeger for the Council, 1975
Buku Teks
Meier, Gerald M., author
Oxford University Press, 1984
Buku Teks
Zed Books, 1993
Buku Teks