Creighton, Donald, author
Macmillan, 1957
Buku Teks
Day, Arthur R
Wesview Press, 1986
Buku Teks
Sehlesinger, Arthur M.
Harper & Row, 1945
Buku Teks
Lord, Barry, author
NC Press, 1974
Buku Teks
Harper, J. Russell.
University of Toronto Press , 1966
Buku Teks