Saito, S.M.T. and Neptune, A.M.L. 1976. Effect of organic matter and of a nitrification inhibitor "AM" on the uptake of 15NH4 and 15NO3 by maize . Anais da Escola Superior de Agricultura Luiz de Queiroz. 33, (Jan. 1976), 721–750. DOI:https://doi.org/10.1590/S0071-12761976000100060.