Goode, Roy, author
Penguin Books, 2004
Buku Teks
Bradgate, Robert, author
Butterworth, 1991
Buku Teks
Simpson, Laurence P., author
Alexander Hamilton Institute, 1961
Buku Teks
Adams, Kristen David, author
St. Paul, MN : West Group, 2010
Buku Teks
Macintryre, Ewan, author
Blackstone Press, 1998
Buku Referensi