Canning, Joseph
Routledge, 1996
Buku Teks
Brint, Michael, author
Westview Press, 1991
Buku Referensi
Germino, Dante L., author
Rand McNally, 1972
Buku Teks
Ellsworth, John W
McGraw-Hill, 1976
Buku Teks
edited by David Ingram
Blackwell , 2002
Buku Teks