Pritchard, Leleand J.
Hougton Mifflin Company, 1958
Buku Teks
Steiner, William Howard, author
Henry Holt, 1956
Buku Teks
Luckett, Dudley G., author
McGraw-Hill , 1984
Buku Teks
Bradford, Frederick A., author
Longmans, Green, 1939
Buku Teks
Bradford, Frederick A., author
Longmans, Green, 1933
Buku Teks