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Dyfyniad Arddull ChicagoNo 2. 2020, 2020. https://doi.org/10.18799/24056537/2020/2.
Dyfyniad MLANo 2. 2020, 2020. https://doi.org/10.18799/24056537/2020/2.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.