I'm currently an undergraduate freshman looking for resources to self-read Industrial Organization. I've read Varian's undergraduate book cover-to-cover and have a decent understanding of basic game theory, and I own the book Industrial Organization: Theory and Applications by Pepall-Richards-Norman
Is there another book that would be better for someone who wants a rigorous treatment of IO that is mathematically advanced but theoretically digestable, or is this one optimal? (By the time I begin to self-read, I'll have finished most of baby Rudin).