Dyfyniad APA

(1981). British National Bibliography. British library bibliographic division.

Dyfyniad Arddull Chicago

British National Bibliography. London: British library bibliographic division, 1981.

Dyfyniad MLA

British National Bibliography. British library bibliographic division, 1981.

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