TY  - RPRT
TI  - The alpha spending function approach to interim data analyses.
AU  - D L DeMets
AU  - G Lan
PY  - 1995
DO  - 10.1007/978-1-4615-2009-2_1
UR  - https://pubmed.ncbi.nlm.nih.gov/7640159/
ID  - 7640159
ER  -