Adami, Paulo Fernando, et al. “Grazing Intensities and Poultry Litter Fertilization Levels on Corn and Black Oat Yield”. Pesquisa Agropecuaria Brasileira, vol. 47, no. 3, Apr. 2012, pp. 360-8, doi:10.1590/S1678-3921.pab2012.v47.10365.