@misc{indiciae539335f871d9,
  title = {Development and calibration of a pressure-difference bedload sampler},
  author = {Edward J. Helley and Winchell Smith},
  year = {1971},
  doi = {10.3133/ofr73108},
  url = {https://pubs.usgs.gov/publication/ofr73108},
  note = {Source identifier: ofr73108}
}