@misc{indiciaee271e31bf2e7,
  title = {Note on a Canonical Form for the Linear q-Difference System.},
  author = {G D Birkhoff and P E Guenther},
  year = {1941},
  doi = {10.1073/pnas.27.4.218},
  url = {https://pubmed.ncbi.nlm.nih.gov/16578011/},
  note = {Source identifier: 16578011}
}