@misc{indiciae26a681544e31,
  title = {Note on Linear Difference and Differential Equations.},
  author = {G D Birkhoff},
  year = {1941},
  doi = {10.1073/pnas.27.1.65},
  url = {https://pubmed.ncbi.nlm.nih.gov/16588429/},
  note = {Source identifier: 16588429}
}