Baudichau, A., Bruyer, DC., Ontiveros, R., & Shermer, WD. (1987). A Rapid Hplc Method for the Determination of Methionine Hydroxy Analog Free Acid in Supplemented Feeds. Journal of the Science of Food and Agriculture, 38(1), 1-8. https://doi.org/10.1002/jsfa.2740380103 (Original work published 1987)