Volume I. Direct Requirements Tables
United States. Bureau of Labor Statistics. "Volume I. Direct Requirements Tables" in Historical and Projected Input-Output Tables of the Economic Growth Project : Bulletin of the United States Bureau of Labor Statistics, No. 2056 (1980). https://fraser.stlouisfed.org/scribd/?item_id=499663&filepath=/files/docs/publications/bls/bls_2056_1980_v1.pdf&start_page=1, accessed on August 21, 2017.