P. Gunawardana, G. Wu, K. Yuan, M. Bryant, and D. Roland, Sr., “Effect of Dietary Protein and Peptide in Corn-Soy Diets on Hen Performance,Egg Solids, Egg Composition and Egg Quality of Hy-Line W- 36 Hens During Second Cycle Phase Three”, Int. J. Poult. Sci., vol. 8, no. 4, pp. 317–322, Mar. 2009, doi: 10.3923/ijps.2009.317.322.