Helrich Kenneth <br/><br/>
Official Methods of Analysis of the association of Official 

 - 15th ed. 
 - U.S.A  The Association of Official A  nalytical C1990 
 - xxiv,684p, 
<br/><br/><label>ISBN: </label>935584420 
<br/><br/><label>Dewey Class. No.: </label>631.41