1. AOAC Official Method 974.29. Vitamin A in Mixed Feeds, Premixes, and Human and Pet Foods Colorimetric Method. AOAC International.
2. BS EN 12823–1:2000. Foodstuffs. Determination of vitamin A by high performance liquid chromatography. Measurement of all-trans-retinol and 13-cis-retinol.
3. Collaborative study: Determination of retinol and carotene by high-performance liquid chromatography;Bueno;Food Chemistry,1997
4. How proficiency testing can improve the quality of analytical data using vitamin analysis as an example;Earnshaw;Food Chemistry,2009
5. EC 90/496. Council Directive of 24 September 1990 on nutrition labelling for foodstuffs. Official Journal of the European Communities, L276/40–44.