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Dyfyniad Arddull ChicagoPolit, Denise F. Nursing Research: Principles and Methods. 4th ed. Philadelphia: Lippincott, 1991.
Dyfyniad MLAPolit, Denise F. Nursing Research: Principles and Methods. 4th ed. Lippincott, 1991.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.