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Dyfyniad Arddull ChicagoOMS. Recent Advances in Fertility Regulation. Genève: OMS, 1981.
Dyfyniad MLAOMS. Recent Advances in Fertility Regulation. Genève: OMS, 1981.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.