TY  - RPRT
TI  - Group sequential methods for cluster randomization trials with binary outcomes.
AU  - Guang Yong Zou
AU  - Allan Donner
AU  - Neil Klar
PY  - 2005
DO  - 10.1191/1740774505cn126oa
UR  - https://pubmed.ncbi.nlm.nih.gov/16422308/
ID  - 16422308
ER  -