Where do I find information about guitarists styles.?

I am doing a research paper for school, and I want to do it as an asis of the guitar styles of a famous guitarist. I am thinking probably either Slash, Vaughan, Santana, or maybe Kirk Hammet. Like their roots, other bands with similar styles, different techniques they use to get their sound, but I don't know where to start. Does anybody know where I can find this information? I don't really have a preference. Just depends on which I find the most information for.