Brint, Michael, author
Westview Press, 1991
Buku Referensi
Sharma, R.P., author
Sterling Publishers Private, 1984
Buku Teks
Bowle, John
J. Cape, 1947
Buku Teks
Germino, Dante L., author
Rand McNally, 1972
Buku Teks
McClelland, J.S.
Routledge , 1998
Buku Teks