Measurement uncertainty from validation and duplicate analysis results in HPLC analysis of multivitamin preparations and nutrients with different galenic forms, De Beer, J., Baten P., Nsengyumva C., and Smeyers-Verbeke J. , J.Pharm.Biomed.Anal., 8/8/2003, Volume 32, Issue 4-5, Number 811, p.767 - 811, (2003)