Smyth, Thomas Jot, and Joaquim Braga Bastos. 2014. “Phosphorus Fertilization for Corn and Cowpeas on a Typic Acrorthox in the Humid Tropics”. Pesquisa Agropecuaria Brasileira 20 (11):1259-64. https://doi.org/10.1590/S1678-3921.pab1985.v20.16333.