@misc{indiciae88eacdb9b39d,
  title = {Open-channel intergrating-type flow meter},
  author = {F. C. Koopman},
  year = {1971},
  doi = {10.3133/ofr71173},
  url = {https://pubs.usgs.gov/publication/ofr71173},
  note = {Source identifier: ofr71173}
}