@misc{indiciae91efcac4810d,
  title = {Group sequential testing in clinical trials with multivariate observations: a review.},
  author = {J W Lee},
  year = {1994},
  doi = {10.1002/sim.4780130202},
  url = {https://pubmed.ncbi.nlm.nih.gov/8122047/},
  note = {Source identifier: 8122047}
}