Millard, Thomas F., author
Century, 1916
Buku Teks
Chamberlin, William Henry
Duckworth, 1940
Buku Teks
Quigley, Harold S., author
World Peace Foundation, 1938
Buku Teks
Latourette, Kenneth Scott, author
Macmillan, 1952
Buku Teks
Kohler, Heinz, author
Frederick A. Praeger, 1965
Buku Teks