1. Becker, R., Chambers, J.M. and Wilks. A. (1988), The New S language, Wadsworth, Belmont CA.
2. McCullagh, P. and Nelder, J. (1983), Generalized Linear Models, Chapman and Hall, London.
3. Hastie, T. and Tibshirani, R. (1990), Generalized Additive Models, (in press) Chapman and Hall, London.