@misc{indiciae41933c8a7292,
  title = {Topographic instructions, Book 3, multiplex procedure; Chapter 3 C7a-e},
  author = {Edward I. Loud},
  year = {1952},
  doi = {10.3133/cir164},
  url = {https://pubs.usgs.gov/publication/cir164},
  note = {Source identifier: cir164}
}