Penn, G. (1955). "Up funnel, down screw!": The story of the Naval Engineer. Hollis & Carter.
Dyfyniad Arddull ChicagoPenn, Geoffrey. "Up Funnel, Down Screw!": The Story of the Naval Engineer. London: Hollis & Carter, 1955.
Dyfyniad MLAPenn, Geoffrey. "Up Funnel, Down Screw!": The Story of the Naval Engineer. Hollis & Carter, 1955.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.