@misc{indiciaef00e7fb2dbe7,
  title = {The fractionation of humic acids from natural water systems},
  author = {R.L. Wershaw and D.J. Pinckney},
  year = {1973},
  url = {https://pubs.usgs.gov/publication/70160709},
  note = {Source identifier: 70160709}
}