IBM 2501 (English Wikipedia)

Analysis of information sources in references of the Wikipedia article "IBM 2501" in English language version.

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1books.google.com

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bitsavers.org

IBM Corporation (1967). IBM Field Engineering Theory of Operation: 2501 Card Reader Model A (PDF). Retrieved March 12, 2021.
IBM 1130 Functional Characteristics (PDF) (seventh ed.). IBM. April 1972. p. 3. GA26-5881-6.
IBM Corporation (November 1969). IBM 1130 Computing System, IBM System/360 Models 25, 30, 40, 44, 50, 65, and IBM System/360 Model 20-Special Feature Description Optical Mark Reading for IBM 2501 Card Reader and IBM 2560 Multi-Function Card Machine (PDF). Retrieved March 12, 2021.

books.google.com

University of Michigan (September 1980). Introduction to the Computing Center. p. 93. Retrieved July 29, 2016.

columbia.edu

Da Cruz, Frank. "The IBM 2501 Card Reader". Columbia University Computing History. Columbia University. Retrieved July 29, 2016.

ibm.com

IBM Corporation. "Identifying I/O device requirements". IBM Knowledge Center. Retrieved July 29, 2016.

ibm1130.net

Shubs, Howard. "Punched Card Input/Output Devices". IBM1130.net. Retrieved July 29, 2016.