Reading GHC Core

Core is GHC's intermediate language. Reading Core can help you better understand the performance of your program. Someone asked me for documentation or tutorials on reading Core, but I couldn't find much.

What documentation is available for reading GHC Core?

Here's what I've found so far:

• Write Haskell as fast as C: exploiting strictness, laziness and recursion
• Haskell as fast as C: working at a high altitude for low level performance
• RWH: Chapter 25. Profiling and optimization
• High-Performance Haskell talk at CUFP (slide 65-80)