Megarry, Robert, author
Stevens and Sons, 1975.
Buku Teks
Khublall, N., author
Butterworths, 1996
Buku Teks
Burby, William Edward, 1893-, author
West Publishing, 1954
Buku Teks
Brown, Ray Andrews, author
Callaghan & Company, 1955
Buku Teks
Boyer, Ralph E., author
St. Paul Minn, 1991
Buku Teks