Hi everyone, I just learned that before Athena there was no such program to check on all combinations, so it was not that confusing - or just more work? I think this feature of Athena is very good tool, but when I really do not know what is in my sample how can it help? I try to answer it myself and someone can correct me: Certainly not all of my, say 10 reference spektra, are that similar that I can get several LCFs with the same say R-factor. So, I will get some clue to narrow the components. But still there can be, for example: Standard-combi 1, 2, 3 equal to 1, 4, 6. So, my analysis gives two solutions and one must be wrong, but both can be wrong. How can I tell? Can a PCA help me in this case? The results change significantly when I change the normalization. How do I know what is the 'correct' adjustment? - Yes, I read the Athena turorials, but I got no answers from there. I searched quite a while to find a complete documentation of the LCF formula used in Athena, but I could not find it. Many thanks, Lisa