@misc{indiciae89e2251cd63b,
  title = {Generalized potentiometric surface of the Sparta-Memphis aquifer, eastern Arkansas, spring 1980},
  author = {D. J. Ackerman},
  year = {1987},
  doi = {10.3133/wri874282},
  url = {https://pubs.usgs.gov/publication/wri874282},
  note = {Source identifier: wri874282}
}