TY  - RPRT
TI  - Practical problems in interim analyses, with particular regard to estimation.
AU  - S J Pocock
AU  - M D Hughes
PY  - 1989
DO  - 10.1016/0197-2456(89)90059-7
UR  - https://pubmed.ncbi.nlm.nih.gov/2605969/
ID  - 2605969
ER  -