O`Neill, William L.
The progressive years : America comes of age
Harper & Row Publishers, 1975
 Buku Teks
Drucker, Peter Ferdinand, 1909-2005
America's next twenty years
Harper & Brothers, 1957
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Tocqueville, Alexis de
Democracy in America
A Mentor Book, 1956
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Tocqueville, Alexis de
Democracy in America
Oxford University Press, 1961
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Tocqueville, Alexis de
Democracy in America
Schocken Books, 1961
 Buku Teks