Agnew, P. L. (1942). Office machines course: Full keyboard adding listing machine, ten-key adding listing machine, crank-driven calculator, key-driven calculator. South-western Pub. Co..
Chicago-viite (17. p.)Agnew, Peter Lawrence. Office Machines Course: Full Keyboard Adding Listing Machine, Ten-key Adding Listing Machine, Crank-driven Calculator, Key-driven Calculator. Cincinnati : New York: South-western Pub. Co., 1942.
MLA-viite (8. p.)Agnew, Peter Lawrence. Office Machines Course: Full Keyboard Adding Listing Machine, Ten-key Adding Listing Machine, Crank-driven Calculator, Key-driven Calculator. South-western Pub. Co., 1942.
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