@misc{indiciae8b02692355ee,
  title = {When is a cluster?},
  author = {J Berger and A Manz},
  year = {1993},
  doi = {10.1016/0140-6736(93)92690-u},
  url = {https://pubmed.ncbi.nlm.nih.gov/8104267/},
  note = {Source identifier: 8104267}
}