@misc{indiciae5fd701b92953,
  title = {On the Time Average Theorem in Dynamics.},
  author = {E Hopf},
  year = {1932},
  doi = {10.1073/pnas.18.1.93},
  url = {https://pubmed.ncbi.nlm.nih.gov/16577437/},
  note = {Source identifier: 16577437}
}