(en) Ronald Powaski, Toward an Entangling Alliance : American Isolationism, Internationalism, and Europe, 1901–1950, Westport, Greenwood, (lire en ligne), p. 72.
(en) Douglas Brinkley et David Rubel, World War II : The Axis Assault, 1939-1942, Macmillan, (lire en ligne), p. 99–106.
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(en) Jerald A. Combs, Embargoes and Sanctions, Encyclopedia of American Foreign Policy, 2002.