Borges, Bruno Samuel, et al. “Digestible Tryptophan Levels for Male Broilers in Pre-Starter and Starter Diets”. Semina: Ciências Agrárias, vol. 37, no. 4Supl1, Sept. 2016, pp. 2529-38, doi:10.5433/1679-0359.2016v37n4Supl1p2529.