@INBOOK {VANLAUWE:2001e, title = {Direct interactions between N fertilizer and organic matter: evidence from trials with 15N-labeled fertilizer}, author = {Vanlauwe, B. and Diels, J. and Aihou, K. * and Iwuafor, E. * and Lyasse, O. and Sanginga, P. and Merckx, R. }, editor = {Vanlauwe, B. and Diels, J. and Sanginga, P. and Merckx, R. }, year = {2001}, type = {Integrated plant nutrient management in sub-Saharan Africa: from concept to practice}, pages = {173--178}, publisher = {Wallingford}, address = {UK: CABI;}, }