# Resolution exponential lower bound… alternative proofs?

I am reading the Resolution proof system exponential lower bound via Haken's bottleneck method for the Pigeonhole Principle as presented in Arora and Barak's Computational Complexity: A Modern Approach, Chapter 15. However, I don't like how the proof is presented in the book and I am having some difficulties following it.

Does somebody know of alternative sources where this same proof is presented? I know there are different techniques to show exponential lower bounds for Resolution, but I want something based on the Pigeonhole Principle. It's just that the phrasing in this book is truly confusing.