Sampaio, José Paulo Braga, et al. “Feed Preference in Broiler Fed Diets Containing Different Energetic Densities”. Pesquisa Agropecuaria Brasileira, vol. 26, no. 10, Oct. 1991, pp. 1803-8, doi:10.1590/S1678-3921.pab1991.v26.3528.