@misc{indiciae1c2a2e2f2dd9,
  title = {Developments in cluster randomized trials and Statistics in Medicine.},
  author = {M J Campbell and A Donner and N Klar},
  year = {2007},
  doi = {10.1002/sim.2731},
  url = {https://pubmed.ncbi.nlm.nih.gov/17136746/},
  note = {Source identifier: 17136746}
}