11.11.11. 490/06.2.2.3: Organisation for economic co-operation and development (OECD).
Dyfyniad Arddull Chicago11.11.11. 490/06.2.2.3: Organisation for Economic Co-operation and Development (OECD).
Dyfyniad MLA11.11.11. 490/06.2.2.3: Organisation for Economic Co-operation and Development (OECD).
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.