Dyfyniad APA

Lessenberry, D. D. (1942). 20th century typewriting (4th ed.). South-western Pub. Co..

Dyfyniad Arddull Chicago

Lessenberry, D. D. 20th Century Typewriting. 4th ed. Cincinnati : New York [etc.]: South-western Pub. Co., 1942.

Dyfyniad MLA

Lessenberry, D. D. 20th Century Typewriting. 4th ed. South-western Pub. Co., 1942.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.