Nursing reseach :   principles and methods / 
Denise F. Polit, Bernadette P. Hungler 
 - 4th ed. 
 - New York :  J. B. Lippincott,  1991. 
 - xiv, 697 p. :  ill. ;  25 cm. 
<br/><br/><label>ISBN: </label>0397548206 
<br/><br/><label>LC Class. No.: </label>RT81.5   / .P64 1991