1. Morgan J, Sonquist J (1963). Problems in the analysis of survey data and a proposal. J Am Stat Assoc 58:415–434.
2. Breiman L, Friedman J, Olshen R, Stone C (1984). Classification and Regression Trees. Wadsworth International Group.
3. Becker R, Chambers J, Wilks A (1988). The New S Language. Wadsworth International Group.
4. Clark L, Pregibon D (1992). Tree-based models. In Statistical Models in S. Wadsworth International Group.
5. Cox DR (1972). Regression models and life tables. J R Stat Soc B 34:187–200.