Hall, W. J., and Wellner, J. A. (1980). “Confidence Bands for a Survival Curve from Censored Data.” Biometrika 67:133–143.
Kaplan, E. L., and Meier, P. (1958). “Nonparametric Estimation from Incomplete Observations.” Journal of the American Statistical Association 53:457–481.
Klein, J. P., and Moeschberger, M. L. (1997). Survival Analysis: Techniques for Censored and Truncated Data. New York: Springer-Verlag.