“Effects of Tannins As Constituents of Sorghum Grain on Broiler Chicks Growth, Protein Digestibility and Some Minerals Availability”. The Sudan Journal Of Animal Production المجلة السودانية للانتاج الحيواني, vol. 15, no. 15, June 2002, p. 13, https://sud-jap.sd/Journal/index.php/sjap/article/view/140.