@misc{indiciae4bcd267aa4ef,
  title = {Sample size determination using an interim analysis.},
  author = {D R Bristol},
  year = {1993},
  doi = {10.1080/10543409308835057},
  url = {https://pubmed.ncbi.nlm.nih.gov/8220401/},
  note = {Source identifier: 8220401}
}