@misc{indiciae13435e1d1b93,
  title = {On Difference Sets.},
  author = {S Chowla},
  year = {1949},
  doi = {10.1073/pnas.35.2.92},
  url = {https://pubmed.ncbi.nlm.nih.gov/16588865/},
  note = {Source identifier: 16588865}
}