Mason, Edward S.
Claremont College for the four associated colleges at Claremont, 1955
Buku Teks
Kemmerer, Donald L.
Littlefield, Adams, 1956
Buku Teks
Beard, Charles A.
Macmillan, 1957
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Parks, Wallace Judson
Johns Hopkins Press, 1951
Buku Teks
Rosinger, Lawrence K.
Macmillan, 1950
Buku Teks