@misc{indiciaea3177737e71a,
  title = {The chemical structure of highly aromatic humic acids in three volcanic ash soils as determined by dipolar dephasing NMR studies},
  author = {Patrick G. Hatcher and M. Schnitzer and A. M. Vassallo and M. A. Wilson},
  year = {1989},
  doi = {10.1016/0016-7037(89)90278-0},
  url = {https://pubs.usgs.gov/publication/70015908},
  note = {Source identifier: 70015908}
}