Ross,David. (2005). Advocacy.
Dyfyniad Arddull ChicagoRoss,David. Advocacy. Australia, 2005.
Dyfyniad MLARoss,David. Advocacy. 2005.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.
Ross,David. (2005). Advocacy.
Dyfyniad Arddull ChicagoRoss,David. Advocacy. Australia, 2005.
Dyfyniad MLARoss,David. Advocacy. 2005.