APA-referens (7:e uppl.)

Truesdell, L. E. (1965). The development of punch card tabulation in the Bureau of the Census, 1890-1940, with outlines of actual tabulation programs/ Leon Edgar Truesdell. U.S. Dept. of Commerce.

Chicago-referens (17:e uppl.)

Truesdell, Leon Edgar. The Development of Punch Card Tabulation in the Bureau of the Census, 1890-1940, with Outlines of Actual Tabulation Programs/ Leon Edgar Truesdell. Washington: U.S. Dept. of Commerce, 1965.

MLA-referens (9:e uppl.)

Truesdell, Leon Edgar. The Development of Punch Card Tabulation in the Bureau of the Census, 1890-1940, with Outlines of Actual Tabulation Programs/ Leon Edgar Truesdell. U.S. Dept. of Commerce, 1965.