@misc{indiciae158396b88ef9,
  title = {The differential fee.},
  author = {R J Smith},
  year = {1970},
  doi = {10.5694/j.1326-5377.1970.tb116761.x},
  url = {https://pubmed.ncbi.nlm.nih.gov/5428149/},
  note = {Source identifier: 5428149}
}