Dyfyniad APA

Proceedings of the institution of civil engineers September 1957.

Dyfyniad Arddull Chicago

Proceedings of the Institution of Civil Engineers September 1957.

Dyfyniad MLA

Proceedings of the Institution of Civil Engineers September 1957.

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