@misc{indiciae13c1f0ab0a82,
  title = {Current advances in sampling theory: implications for human observational studies.},
  author = {R M Royall},
  year = {1976},
  doi = {10.1093/oxfordjournals.aje.a112317},
  url = {https://pubmed.ncbi.nlm.nih.gov/970403/},
  note = {Source identifier: 970403}
}