"An Introduction to Computing with Haskell" by Manuel M. T. Chakravarty and Gabrielle C. Keller, Pearson SprintPrint, 2002, ISBN 1 74009 404 2.

Mike Thomas "An Introduction to Computing with Haskell" by Manuel M. T. Chakravarty and Gabrielle C. Keller, Pearson SprintPrint, 2002, ISBN 1 74009 404 2. 247-249 2004 14 J. Funct. Program. 2 http://dx.doi.org/10.1017/S0956796803215033 db/journals/jfp/jfp14.html#Thomas04