Barker, D. J.P.  <br/><br/>
Practical epidemiology / 
Barker, D. J.P. and Hall, A. J. 
 - U K:  ELBS,  1973. 
<br/><br/><label>ISBN: </label>9780443044243 
<br/><br/><label>Dewey Class. No.: </label>614.40723  / BAR