Holman, C. Hugh, author
Macmillan, 1986
Buku Referensi
Crawford, Bartholow V.
Barnes & Noble, Inc., 1953
Buku Teks
Holland, Norman Norwood, author
Oxford Universiy Press, 1990
Buku Referensi
Eaglestone, Robert, author
Routledge , 2005
Buku Teks
edited by Clarence L. Barnhart
Appleton-Century-Crofts, 1956
Buku Referensi