Lien, R.J., et al. “Influence of 2-Hydroxy-4-(Methylthio)butanoic Acid on Early Egg and Chick Weights of Broiler Breeders”. International Journal of Poultry Science, vol. 2, no. 6, Oct. 2003, pp. 430–437, https://doi.org/10.3923/ijps.2003.430.437.