Kenneth Helrich <br/><br/>
Official methods of analysis of the association of 
Kenneth Helrich 
 - Ed 15 
 -  Association Of Official Analytical Chemists  1990 
<br/><br/><label>ISBN: </label> 12457.4 
<br/><br/><label>Dewey Class. No.: </label>543HEL.N0.1