@misc{indiciae2eaa67aebc72,
  title = {The difference between the potentiometric surfaces of the lower Patapsco aquifer in southern Maryland, September 1990 and September 2007},
  author = {Stephen E. Curtin and David C. Andreasen and Andrew W. Staley},
  year = {2009},
  doi = {10.3133/ofr20091087},
  url = {https://pubs.usgs.gov/publication/ofr20091087},
  note = {Source identifier: ofr20091087}
}