Reference

Construct monitoring boundaries Functions to compute rejection boundaries
get.boundaries.design()	Get Pocock or OBF-style boundaries at the design stage
get.boundaries.aspend()	Derive boundaries with alpha-spending.
Get adjusted p-values Functions to compute adjusted p-values
get.pvalue.sw()	Get a stage-wise p-value after the trial is complete.
Alpha-spending Alpha-spending functions
pocock.spend()	Pocock approximation, alpha spending function
obf.spend()	O'Brien-Fleming approximation, alpha spending function