Roemer, Milton I., author
Oxford University Press, 1991
Buku Referensi
Mackintosh, Douglas R.
Westview Press, 1978
Buku Teks
Bury, Michael, author
Routledge, 2000
Buku Teks
Porter-O`Grady, Tim, author
Mosby, 1998
Buku Teks
Irina Farquhar, Kent Summers, Alan Sorkin, editor
JAI, 2001
Buku Teks