O'Hara, W. J. (1951). Mariner's gyro - navigation manual for masters, mates, marine engineers and potential ship's officers. Cornell maritime press.
Dyfyniad Arddull ChicagoO'Hara, Walter J. Mariner's Gyro - Navigation Manual for Masters, Mates, Marine Engineers and Potential Ship's Officers. Cambridge: Cornell maritime press, 1951.
Dyfyniad MLAO'Hara, Walter J. Mariner's Gyro - Navigation Manual for Masters, Mates, Marine Engineers and Potential Ship's Officers. Cornell maritime press, 1951.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.