Costain, T. B. (1960). The Chord of Steel: Alexander Graham Bell and the invention of the telephone. New York: Doubleday and Company.
Παραπομπή Chicago StyleCostain, Thomas B. The Chord of Steel: Alexander Graham Bell and the Invention of the Telephone. New York: Doubleday and Company, 1960.
Παραπομπή MLACostain, Thomas B. The Chord of Steel: Alexander Graham Bell and the Invention of the Telephone. New York: Doubleday and Company, 1960.
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