@misc{indiciae473e02e707b1,
  title = {A simple high-precision Jacob's staff design for the high-resolution stratigrapher},
  author = {William P. Elder},
  year = {1989},
  doi = {10.2307/3514607},
  url = {https://pubs.usgs.gov/publication/70015990},
  note = {Source identifier: 70015990}
}