Methods for evaluating biological Nitrogen fixation  edited by F.J. Bergersen. 

 - New York  John Wiley and Sons  1980 
 - x, 702p., ill. 27cm. 
<br/><br/><label>ISBN: </label>047-27759-2. 
<br/><br/><label>Dewey Class. No.: </label>581.13354,  / M57M