Polit, D. F. Nursing research : principles and methods / Denise F. Polit and Bernadette P. Hungler. - 6th ed. - Philadelphia : Lippincott, 1999. - xviii, 757 p. : ill.;Hbk ISBN: 0781715628 Subjects--Topical Terms: Nursing--Research--Methodology.Nursing Research--methods. LC Class. No.: RT81.5.P64 / 1999