Board of Governors of the Federal Reserve System (U.S.), 1935-. "Date Availability for Preliminary Estimates: 1987.Q4," in Board of Governors of the Federal Reserve System (U.S.), 1935-. "March 11, 1988," Z.1 Financial Accounts of the United States (1988-03-11) : 6-7. https://fraser.stlouisfed.org/title/93/item/69079/toc/483948 , accessed on April 23, 2024.