@book{9266,
	author = {Polit, Denise F. and Hungler, Bernadette P.},
	title = {Essentials of nursing research: methods, appraisals, and utilization. /},
	publisher = {Lippincott-Raven,},
	year = {1997.},
	address = {Philadelphia:},
	edition = {4th ed.}
}