Narvaez-Solarte, William, Horacio Santiago Rostagno, Paulo Rubens Soares, Marcelo A. Silva, and Luis Fernando Uribe-Velasquez. 2005. “Nutritional Requirements in Methionine + Cystine for White-Egg Laying Hens During the First Cycle of Production”. International Journal of Poultry Science 4 (12): 965–968. https://doi.org/10.3923/ijps.2005.965.968.