H. Akpan, E. Udosen, A. Udofia, E. Akpan, and A. Joshua, “The Effect of Phytase and Zinc Supplementation on Palm Kernel Cake Toxicity in Sheep”, Pak. J. Nutr., vol. 4, no. 3, pp. 148–153, Apr. 2005, doi: 10.3923/pjn.2005.148.153.