Lessenberry, D. D., & Crawford, T. J. (1947). 20th century typewriting (4th ed.). South-western Publishing Co..
Dyfyniad Arddull ChicagoLessenberry, D. D., and T. James Crawford. 20th Century Typewriting. 4th ed. [Cincinnati] : [New York, etc.: South-western Publishing Co., 1947.
Dyfyniad MLALessenberry, D. D., and T. James Crawford. 20th Century Typewriting. 4th ed. South-western Publishing Co., 1947.
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