Among the available works of reference, one of the most useful is Wayne Bray, The Controversy Over a New Canal Treaty between the United States and Panama: A Selective Annotated Bibliography of United States, Panamanian, Colombian, French, and International Organization Sources (Washington, D.C., 1976). From the Panamanian side, see Nydia Cardozo and Consuelo Tempone, Guía para investigadores de Panamá (Panama City, 1978); and from the Canal Zone, see Subject Catalog of the Special Panama Collection of the Canal Zone Library-Museum (Boston, 1964). The most comprehensive collection of documentary material is Library of Congress, Congressional Research Service, Background Documents Relating to the Panama Canal (Washington, D.C., 1977). An indispensable primary source is the printed State Department material, successively entitled Papers Relating to the Foreign Relations of the United States, Foreign Relations of the United States: Diplomatic Papers and Foreign Relations of the United States. For a Zone perspective, see the annual reports of the chairman of the Isthmian Canal Commission for the years 1904 to 1914, of the governor of the Panama Canal for the years 1914 to 1951, and of the president of the Panama Canal Company for the years 1951 to 1979 (Washington, D.C., 1904–79). Bringing the Zone graphically to life in the period 1904–39 is the Panama Canal Photograph Collection, held in Record Group 185 in the U.S. National Archives, Washington, D.C., while note should also be taken of two excellent documentary films: Frederick Wiseman’s ‘Canal Zone’ (1977) and Carl Charlson’s ‘A man, a plan, a canal: Panama’ (1987).