作表機
↑ Columbia University Computing History - Herman Hollerith
↑ Truedsell, Leon E. (1965). The Development of Punch Card Tabulation in the Bureau of the Census 1890-1940. US GPO. p. 51
↑ [-245-] An Electric Tabulating System, The Quarterly, Columbia University School of Mines, Vol.X No.16 (April 1889)
↑ IBM Archive: Hollerith Tabulator & Sorter Box
↑ U.S. Census Bureau: The Hollerith Machine
1 2 U.S. Census Bureau: Tabulation and Processing