@INBOOK {LIYA:1990a, title = {Estimation of N2 fixation by nitrogen-fixing trees in the subhumid tropics using 15N dilution and difference methods}, author = {Liya, S. M. and Odu, C. T. I. and Agboola, A. A. and Mulongoy, K. }, year = {1990}, type = {Use of stable isotopes in plant nutrition, soil fertility and environmental studies. International Symposium, 1-5 Oct 1990, Vienna, Austria}, pages = {190--192}, publisher = {International Atomic Energy Agency}, address = {Vienna, Austria}, }