@book{9299,
	author = {Polit, Denise F. and Beck, Cheryl Tatano},
	title = {Essentials of nursing research : appraising evidence for nursing practice},
	publisher = {Lippincott Williams & Wilkins},
	year = {2010},
	address = {Philadelphia},
	edition = {7 th ed},
	note = {Includes bibliographical references and index}
}