Lessenberry, D. D. (1942). 20th century typewriting (4th ed.). South-western Pub. Co..
Čikaški stil citiranja (17. izdanje)Lessenberry, D. D. 20th Century Typewriting. 4th ed. Cincinnati : New York [etc.]: South-western Pub. Co., 1942.
MLA način citiranja (8. izdanje)Lessenberry, D. D. 20th Century Typewriting. 4th ed. South-western Pub. Co., 1942.
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