For more information on the general methods and procedures used for regression with life data, see the following references.
J.D. Kalbfleisch and R.L. Prentice (1980). The Statistical Analysis of Failure Time Data. John Wiley & Sons, Inc.
J.F. Lawless (1982). Statistical Models and Methods for Lifetime Data. John Wiley & Sons, Inc.
W.Q. Meeker and L.A. Escobar (1998). Statistical Methods for Reliability Data. John Wiley & Sons, Inc.
W. Murray, ed. (1972). Numerical Methods for Unconstrained Optimization. Academic Press.
W. Nelson (1990). Accelerated Testing. John Wiley & Sons, Inc.