(2019). Т. 330, № 2. 2019. https://doi.org/10.18799/24131830/2019/2
Dyfyniad Arddull ChicagoТ. 330, № 2. 2019, 2019. https://doi.org/10.18799/24131830/2019/2.
Dyfyniad MLAТ. 330, № 2. 2019, 2019. https://doi.org/10.18799/24131830/2019/2.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.