@misc{indiciae4fca024e98c2,
  title = {A computer program for designing clinical trials with arbitrary survival curves and group sequential testing.},
  author = {J Halpern and B W Brown},
  year = {1993},
  doi = {10.1016/0197-2456(93)90014-5},
  url = {https://pubmed.ncbi.nlm.nih.gov/8500301/},
  note = {Source identifier: 8500301}
}