Liu, Z., et al. “Statistical Sensitivity Required to Detect Any Potential Difference of Bioavailability Between DL-Methionine and DL-Methionine Hydroxy Analogue in Layers”. International Journal of Poultry Science, vol. 3, no. 11, Oct. 2004, pp. 697–703, https://doi.org/10.3923/ijps.2004.697.703.