Dyfyniad APA

Usher , A. P. (1929). A history of mechanical inventions. McGraw-Hill.

Dyfyniad Arddull Chicago

Usher , Abbott Payson. A History of Mechanical Inventions. New York: McGraw-Hill, 1929.

Dyfyniad MLA

Usher , Abbott Payson. A History of Mechanical Inventions. McGraw-Hill, 1929.

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