W. Narvaez-Solarte, H. S. Rostagno, P. R. Soares, M. A. Silva, and L. F. Uribe-Velasquez, “Nutritional Requirements in Methionine + Cystine for White-Egg Laying Hens During the First Cycle of Production”, Int. J. Poult. Sci., vol. 4, no. 12, pp. 965–968, Nov. 2005, doi: 10.3923/ijps.2005.965.968.