@misc{indiciae659a5cf5d0a8,
  title = {Groups, Categories and Duality.},
  author = {S Maclane},
  year = {1948},
  doi = {10.1073/pnas.34.6.263},
  url = {https://pubmed.ncbi.nlm.nih.gov/16588808/},
  note = {Source identifier: 16588808}
}