Where can I found information about the use of dietarysupplements...

www.amazon.com/Adelle-Davis/e/B001J3RULO
www.adelledavis.org/
cronometer.com/ (I haven't tried the software.)

Those are old books, but still the most popular introduction to the field. For more info, go to a library and ask the librarian to help you find some material on nutrition.