McLaughlin, Andrew C., author
Appleton Century Crofts, 1935
Buku Teks
Hacker, Louis M., author
Appleton-Century-Crofts, 1949
Buku Teks
Alden, John Richard, author
American Book Company, 1960
Buku Teks
Hauck, Eldon, author
McFarland, 1991
Buku Referensi
Ritchie, Donald A., author
Macmillan, 1985
Buku Teks