Comptometer (English Wikipedia)

Analysis of information sources in references of the Wikipedia article "Comptometer" in English language version.

refsWebsite

Global rank English rank

4patents.google.com

1,182^nd place

725^th place

1books.google.com

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6^th place

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archive.org

Felt, Dorr E. (1916). Mechanical arithmetic, or The history of the counting machine. Chicago: Washington Institute. p. 4.

books.google.com

Cutter, William Richard (1931). American Biography: A New Cyclopedia. Pub. under the direction of the American historical society. p. 52.

patents.google.com

Hill's Arithmometer patent
U.S. Patent No. 366,945, filed on July 6, 1886
U.S. Patent No. 371,496, filed on March 12, 1887
U.S. Patent No. 405,024, filed on January 19, 1888