PBR resource, plus a cool idea :)

Found this nice work up on physically based materials. He covers a lot of topics and provides links to where he gets some of his information. Not all of it will be relevant to what I am doing with my character, but since I am delving into some aspects of physically based rendering, this could be a good resource for parts of my paper.

"Physically Based Rendering Encyclopedia" by Brian Yu

Also, I really loved the way he displayed his material layering on one of his example renders - showing each material used on a sphere so that you can see its characteristics more clearly. This would be a great way to show the difference in how each render engine's native shaders handle different materials. While it may be difficult to see on a character because of added details, shadows, etc, having the spheres as well makes it very easy to see any difference in how the material renders/responds to light.

Render by Brian Yu