AOAC International. 2007. Official Methods of Analysis, 18th ed., 2005; Current through Revision 2, 2007 (On-line). Method 967.12, AOAC International, Gaithersburg, MD.

Pegg, R.B., Landen, W.O., and Eitenmiller, R.R. 2010. Vitamin analysis. Ch. 11, in Food Analysis, 4th ed. S.S. Nielsen (Ed.), Springer, New York.

Food Analysis Laboratory Manual Second Edition. Springer. edited by S. Suzanne Nielsen. West Lafayette, IN, USA