[R] R validation

[Terry Therneau]

 For the survival package, you might want to reference appendix E of Therneau 
and Grambsh, Modeling Survival Data, Springer-Verlag, 2000.  This contains a set 
of small example data sets for which results have been worked out in closed 
form.  S-plus and R pass all the tests: they are a portion of the test suite of 
the package.  (SAS does not pass, BTW.  It doesn't compute dfbeta residuals for 
a Cox model quite right under the Efron approximation.  The error is small and 
almost certainly unimportant in practical data, but I like to keep it in hand as 
a counterexample to believers of SAS infallability).
 
 	Terry Therneau