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Dyfyniad Arddull ChicagoSigelman, Carol K., and Elizabeth A. Rider. Life-span Human Development. 6th ed. Belmont, Calif: Wadsworth Cengage Learning, 2009.
Dyfyniad MLASigelman, Carol K., and Elizabeth A. Rider. Life-span Human Development. 6th ed. Wadsworth Cengage Learning, 2009.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.