Plamenatz, John, author
National News-Letter, 1949
Buku Teks
Laski, Harold J., author
George Allen and Unwin, 1959
Buku Teks
Sweezy, Paul M. (Paul Marlor), 1910-2004, author
McGraw-Hill, 1949
Buku Teks
edited by Richard M. Ketchum
Dutton , 1955
Buku Teks
Carr, Edward Hallet, author
Macmillan, 1950
Buku Teks