(26 November 1956). Radio Listening: 1948-1956, Broadcasting - Telecasting, p. 34 (chart showing decline of United States radio audience from 1948 to 1956 -- from about 30% average evening ratings in 1948 to under 10% by 1956)
Anthony, Edwin D. (1973). "Records of the Radio Division"(PDF). Records of the Office of Inter-American Affairs. Vol. Inventory of Record Group 229. Washington D.C.: National Archives and Record Services – General Services Administration. pp. 25–26. LCCN73-600146.
Anthony, Edwin D. (1973). "Records of the Radio Division"(PDF). Records of the Office of Inter-American Affairs. Vol. Inventory of Record Group 229. Washington D.C.: National Archives and Record Services – General Services Administration. pp. 25–26. LCCN73-600146.