United States. Department of Commerce and United States. Bureau of Economic Analysis. "Preliminary and Revised Fourth Quarter 1964 and Historical Data," The National Income and Product Account (1965-02-01). https://fraser.stlouisfed.org/scribd/?item_id=57004&filepath=/files/docs/releases/nipa/1960s/nipa_scb021965.pdf&start_page=1, accessed on October 20, 2017.
Preliminary Data for Q4.1964 and Historical Revisions back until 1961