Biological nitrogen fixation and sustainability of tropical agriculture :  proceedings of the Fourth International Conference of the African Association for Biological Nitrogen Fixation (AABNF), held at the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria, 24-28 September 1990 / 
edited by K. Mulongoy, M. Gueye, and D.S.C. Spencer. 
 - Chichester, West Sussex, U.K. ;  New York :  J. Wiley,  c1992. 
 - xiv, 488 p. :  ill. 
<br/><br/><label>ISBN: </label>0471935603 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Nitrogen in agriculture--Tropics.<br/>Nitrogen in agriculture--Africa.<br/>Nitrogen-fixing plants--Tropics.<br/>Nitrogen-fixing plants--Africa.<br/>Cropping systems--Tropics.<br/>Cropping systems--Africa.<br/>Sustainable agriculture--Tropics.<br/>Sustainable agriculture--Africa.<br/>Nitrogen--Fixation