Parker, R. H. (1952). Library applications of punched cards: A description of mechanical systems. American Library Association.
Chicago-referens (17:e uppl.)Parker, Ralph Halsted. Library Applications of Punched Cards: A Description of Mechanical Systems. Chicago: American Library Association, 1952.
MLA-referens (9:e uppl.)Parker, Ralph Halsted. Library Applications of Punched Cards: A Description of Mechanical Systems. American Library Association, 1952.
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