TY  - RPRT
TI  - Simple sample size calculation for cluster-randomized trials.
AU  - R J Hayes
AU  - S Bennett
PY  - 1999
DO  - 10.1093/ije/28.2.319
UR  - https://pubmed.ncbi.nlm.nih.gov/10342698/
ID  - 10342698
ER  -