Pre-punched and pull tab answer card
United States Patent 2798669
US Patent References:
Statistical record
- - 2244231

Circuit connecting device
- - 2478274

Office filing card
- - 2502785

Sorting stamp
- - 2709001


Inventors:
Hale, Merle R.
Publication Date:
07/09/1957
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Assignee:
Hale, Merle R.
Primary Class:
235/489
Other Classes:
434/346
International Classes:
G06K19/02