Apr. 1948-<Apr. 1958>: Department of State publication.
Each number has also a distinctive title.
"Beginning January 1, 1948, the [U.S. Dept. of State] 'Conference series', 'The United States and the United Nations report series' and 'The United States - United Nations information series' are being combined into one comprehensive group ... known as 'The International organization and conference series'."
Various numbers issued by different subordinate Department of State divisions and offices.