There are many introductory Haskell books, but i was (at the time i started learning) keen of those providing also a good basis on functional programming (which was a totally new world for me at the time). ...
R. Hinze, N. Wu, and J. Gibbons. Proceedings of the 18th ACM SIGPLAN International Conference on Functional Programming, page 209--220. New York, NY, USA, ACM, (2013)
P. Hudak, J. Hughes, S. Jones, and P. Wadler. Proceedings of the third ACM SIGPLAN conference on History of programming languages, New York, NY, USA, ACM, (2007)