@misc{indiciaea0720340f2bd,
  title = {Analytical results of insoluble-residue samples from the Paducah 1 degree by 2 degrees Quadrangle, Missouri, Illinois, and Kentucky; drill hole Nos. I30-I70},
  author = {John H. Bullock and H. W. Folger and J. D. Sharkey and C. D. Taylor},
  year = {1991},
  doi = {10.3133/ofr91387b},
  url = {https://pubs.usgs.gov/publication/ofr91387B},
  note = {Source identifier: ofr91387B}
}