@misc{indiciaed644ab540077,
  title = {Index of time-of-travel studies of the US Geological Survey},
  author = {Charles W. Boning},
  year = {1973},
  doi = {10.3133/wri7334},
  url = {https://pubs.usgs.gov/publication/wri7334},
  note = {Source identifier: wri7334}
}