Velz, Clarence J. <br/><br/>
Applied stream sanitation   
by Clarence J. Velz 
 - New York  Wiley  1970 
 - ix, 619p. 
<br/><br/><label>ISBN: </label>0471905259 
<br/><br/><label>LCCN: </label>71-120710 
<br/><br/><label>Dewey Class. No.: </label>628.16  / N702