@misc{indiciaedd51eaed521a,
  title = {Natural aggregate, building America's future},
  author = {William H. Langer and V.M. Glanzman},
  year = {1993},
  doi = {10.3133/cir1110},
  url = {https://pubs.usgs.gov/publication/cir1110},
  note = {Source identifier: cir1110}
}