Anderson, William, 1888-
Holt , 1954
Buku Teks
MacCorkle, Stuart A.
D.C. Heath and Company, 1948
Buku Teks
Judd, Dennis R., author
Little, Brown, 1979
Buku Teks
Hoan, Daniel W.
Harcourt, Brace and Company, 1936
Buku Teks
MacDonald, Austin F., author
Thomas Y. Crowell , 1951
Buku Teks