I've been working my way through this which in my opinion is excellent: http://okmij.org/ftp/Haskell/AlgorithmsH.html#teval http://okmij.org/ftp/Haskell/Algorit

I've been working my way through this which in my opinion is excellent: http://okmij.org/ftp/Haskell/AlgorithmsH.html#teval http://okmij.org/ftp/Haskell/AlgorithmsH.html#teval