@misc{indiciae0df51a384ae1,
  title = {Protection of roads against rock falls},
  author = {Leo Maddalena},
  year = {1948},
  doi = {10.3133/ofr4817c},
  url = {https://pubs.usgs.gov/publication/ofr4817C},
  note = {Source identifier: ofr4817C}
}