Shepard, Clinton L. <br/><br/>
Selected instruction activities and reference 
by Clinton L.  Shepard and James B. Walasak 
 - Ohio  U.S. Environmental protection Agency  1980 
 - 186p.; 22cm.- 
 - Monograph series activated sludge .
<br/><br/><label>Dewey Class. No.: </label>333.91  / SHE