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). ...
E. Meijer, und J. Jeuring. Advanced Functional Programming, First International Spring School on Advanced Functional Programming Techniques-Tutorial Text, Seite 228--266. London, UK, UK, Springer-Verlag, (1995)
J. Gibbons, und G. Jones. Proceedings of the third ACM SIGPLAN international conference on Functional programming - ICFP '98, Seite 273--279. New York, ACM Press, (1998)
E. de Vries, und A. Löh. Proceedings of the 10th ACM SIGPLAN workshop on Generic programming - WGP '14, Seite 83--94. New York, NY, USA, ACM Press, (2014)