Rickard, J.A., author
Barnes & Noble, 1952
Buku Teks
Rickard, J.A.
New York, N.Y. Barner & Noble, Inc. 1956,
Buku Teks
compiled and edited by William L. Langer
Houghton Mifflin, 1968
Buku Referensi
Mayer, Frederick, author
American Book Company, 1950
Buku Teks
Webster, Hutton, author
D.C. Heath, 1947
Buku Teks