@misc{indiciae7b673d08033f,
  title = {Principal facts for gravity stations in the area north of the Grand Canyon in Arizona},
  author = {Peter Popenoe},
  year = {1972},
  doi = {10.3133/70043100},
  url = {https://pubs.usgs.gov/publication/70043100},
  note = {Source identifier: 70043100}
}