Nice write-up. I've generally found the F# source[1] very approachable and easy to peruse. Once you've learned the basics of F# it's a very good place to dig deeper into the language.

Although having said that, the source for FSharp.Control[2] (MailboxProcessor and its support types and functions) still leaves my head spinning somewhat!

[1] https://github.com/fsharp/fsharp

[2] https://github.com/fsharp/fsharp/blob/master/src/fsharp/FSha...