TY  - RPRT
TI  - A simple algorithm for designing group sequential clinical trials.
AU  - D A Schoenfeld
PY  - 2001
DO  - 10.1111/j.0006-341x.2001.00972.x
UR  - https://pubmed.ncbi.nlm.nih.gov/11550952/
ID  - 11550952
ER  -