Dave Benson's "Music: a Mathematical Offering" [1] or my own "Music for Geeks and Nerds" [2]
[1] http://homepages.abdn.ac.uk/mth192/pages/html/maths-music.ht...
Since you can read RWH online, you should, but you should also check out the FPcomplete.com tutorials. Also Simon Thompson's 3rd edition Haskell book is good, probably the only thing I could call a gentle intro to haskell.
also: http://shuklan.com/haskell/
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Finally, there's some ridiculous number of tutorials on the haskell wiki
http://www.haskell.org/tutorial/
It simply groups and layers simple waves until he can describe a full theme. In case you didn't saw it and have 30 minutes of free time.
I really find this book an insight into how to transpose one model into another. It could apply to so much more that music theory, it's just that the author has a predisposition to music and therefore uses it as the illustrative example.