@misc{indiciae81c4ec4e1094,
  title = {An overview of in-stream mining of sand and gravel resources},
  author = {William H. Langer},
  year = {2002},
  doi = {10.3133/ofr02153},
  url = {https://pubs.usgs.gov/publication/ofr02153},
  note = {Source identifier: ofr02153}
}