Vitti, Dorinha Miriam Silber Schmidt, et al. “True Phosphorus Absorption from Different Sources for Sheep, Using Radiophosphorus (P-32)”. Pesquisa Agropecuaria Brasileira, vol. 27, no. 10, Oct. 1992, pp. 1405-8, doi:10.1590/S1678-3921.pab1992.v27.3784.