Phillips, Wendell
Longman, 1967
Buku Teks
Allen, Calvin H., Jr
Westview Press, 1987
Buku Teks
Phillips, Cabell
Macmillan, New York : The Macmillan, c.1966.
Buku Teks
Offices of the Royal Historical society, 1963
Buku Referensi
Holmes, Oliver Wendell
Little, Brown & Co., 1963
Buku Teks