1. AOAC.Official Methods of Analysis, 13th ed.; Horwitz, W., Ed.; Association of Official Analytical Chemists: Washington, DC, 1980; Method 31.111, p 521.
2. AOAC.Official Methods of Analysis,15th ed.; Helrich, K., Ed.; Association of Official Analytical Chemists Inc. Arlington, VA, 1990; Methods 954.11−979.21 and 977.20, pp 1028−1030.
3. ORIGINE BOTANIQUE ET CARACTÉRISTIQUES PHYSICOCHIMIQUES DES MIELS
4. Bergmeyer, H. U.; Bernt, E.Methods of Enzymatic Analysis; Academic Press: New York, 1974; pp 1176−1179.