@misc{indiciae76c36e812a59,
  title = {Countercurrent system.},
  author = {J M Sands and J P Kokko},
  year = {1990},
  doi = {10.1038/ki.1990.261},
  url = {https://pubmed.ncbi.nlm.nih.gov/2232506/},
  note = {Source identifier: 2232506}
}