@INBOOK {KANG:1990b, title = {Agroforestry systems for sustained crop production in the tropics, with special reference to West Africa}, author = {Kang, B. and Van Den Beldt, R. J. }, year = {1990}, type = {American Society of Agronomy Annual Meeting, International Agronomy Section, 28-29 Nov. 1988, Anaheim, California. Edited by E. Moore}, pages = {13--33}, publisher = {Nitrogen Fixing Tree Association}, address = {Waimanalo, Hawaii, USA}, }