1. A.O.A.C. (1970). Official methods of analysis. Washington: A.O.A.C.
2. A.P.S.T.A.C. (1968). Analytical Procedures Subcommitte of the Technical Advisory Committe. Standard Analytical Methods of the Members Companies of Corn Industries Research Foundation. A Division of Corn Refiners Association, Washington, Corn Industrial Research Foundation
3. B?li?,I., Pertot,E., So?i?,H. (1970). J. Steroid Chem.1, 105?110
4. Bowden,J.P., Peterson,W.H. (1946). Arch. Biochem. Biophys.9, 389?399
5. ?apek,A., Han?,O., Kaká?,B., Tadra,M. (1962). Fol. Microbiol.7, 175?179