KaplanMeier-Ref
1. Elisa T. Lee, John Wenyu Wang. 2003. Statistical Methods for Survival Data Analysis, 3th edition. Wiley-Interscience.
2. David W. Hosmer Jr, Stanley Lemeshow. 1999. Applied Survival Analysis: Regression Modeling of Time to Event Data. Wiley-Interscience.
3. Kaplan E. L, and Meier P. 1958. Non-parametric estimation from incomplete observations. J. Amer. Statist. Assoc. Vol. 53, pp 457-481.