1. AOAC 1975 Official Methods of Analysis, ed Association of Official Analytical Chemists, Washington, DC.
2. FAO 1970 Amino Acid Content of Foods and Biological Data on Proteins, FAO Nutritional Studies. Food and Agriculture Organization of the United Nations, Rome, p 285.
3. A spectrophotometric method for the direct determination of cysteine in the presence of other naturally occurring amino acids
4. 1970 Methods in Food Analysis. Academic Press, New York, 20–23.