North american directory of federal, provincial and state weed scientists, Canada, Puerto Rico, United States of America 

 - (s.l. :  s.e.),  (s.a.) 
 - v. 
<br/><br/> La biblioteca tiene: 1979 
<br/><br/><label>LCCN: </label>53314 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Malas hierbas--Investigación--Directorios.
<br/><br/><label>Dewey Class. No.: </label>632.58  / W43