@misc{indiciae48ec89680438,
  title = {Water-quality data for two surface coal mines reclaimed with alkaline waste or urban sewage sludge, Clarion County, Pennsylvania, May 1983 through November 1989},
  author = {D.L. Dugas and C.A. Cravotta and D. A. Saad},
  year = {1993},
  doi = {10.3133/ofr93115},
  url = {https://pubs.usgs.gov/publication/ofr93115},
  note = {Source identifier: ofr93115}
}