TY  - RPRT
TI  - Designs for group sequential tests.
AU  - T R Fleming
AU  - D P Harrington
AU  - P C O'Brien
PY  - 1984
DO  - 10.1016/s0197-2456(84)80014-8
UR  - https://pubmed.ncbi.nlm.nih.gov/6518769/
ID  - 6518769
ER  -