@misc{indiciae81076d12391c,
  title = {Rubel's universal differential equation.},
  author = {R J Duffin},
  year = {1981},
  doi = {10.1073/pnas.78.8.4661},
  url = {https://pubmed.ncbi.nlm.nih.gov/16593068/},
  note = {Source identifier: 16593068}
}