Eckert، W. J.؛ Thomas J. Watson Astronomical Computing Bureau، New York. (1940). Punched card methods in scientific computation. New York: The Thomas J. Watson Astronomical Computing Bureau, Columbia University. مؤرشف من الأصل في 2020-06-12.
Eckert، W. J.؛ Thomas J. Watson Astronomical Computing Bureau، New York. (1940). Punched card methods in scientific computation. New York: The Thomas J. Watson Astronomical Computing Bureau, Columbia University. مؤرشف من الأصل في 2020-06-12.