@misc{indiciae45141b4caf6e,
  title = {On Functions Whose Derivatives Do Not Vanish in a Given Interval.},
  author = {G Polya},
  year = {1941},
  doi = {10.1073/pnas.27.4.216},
  url = {https://pubmed.ncbi.nlm.nih.gov/16578010/},
  note = {Source identifier: 16578010}
}