Foulks, William G.
New York : John Wiley & Sons, 1997,
Buku Teks
compiled by Ernest Dale
Mcgraw-Hill, 1965
Buku Teks
Niles, Olive S.
Georgia Scott 1984
Buku Teks
Stanley, David T.
Brookings Institution, 1963
Buku Teks
Tindal, William York
University of Minneapolis Press, 1961
Buku Teks