@misc{indiciaef2c2606b0469,
  title = {Nitrate contamination of the upper aquifer in the Manatí-Vega Baja area, Puerto Rico},
  author = {Carlos Conde-Costas and Fernando Gomez-Gomez},
  year = {1998},
  url = {https://pubs.usgs.gov/publication/70171274},
  note = {Source identifier: 70171274}
}