Activities of nondiplomatic representatives of foreign principals in the United States : hearings before the Committee on Foreign Relations, United States Senate, Eighty-eighth Congress, first session, under the authority of S. Res. 362, 87th Congress, and S. Res. 26, 88th Congress, authorizing the Committee on Foreign Relations to study the nondiplomatic activities of foreign governments. (U.S. G.P.O.,, 1963)