@misc{indiciae629be20f7b9a,
  title = {Use of solid-state 13C NMR in structural studies of humic acids and humin from Holocene sediments},
  author = {Patrick G. Hatcher and D.L. VanderHart and W.L. Earl},
  year = {1980},
  doi = {10.1016/0146-6380(80)90024-8},
  url = {https://pubs.usgs.gov/publication/70012278},
  note = {Source identifier: 70012278}
}