@misc{indiciaecb7cedc1548f,
  title = {Cluster sampling for immunization coverage.},
  author = {P W Kok},
  year = {1986},
  doi = {10.1016/0277-9536(86)90231-5},
  url = {https://pubmed.ncbi.nlm.nih.gov/3715518/},
  note = {Source identifier: 3715518}
}