@misc{indiciae03be58f908fa,
  title = {Chemical structure of humic acids - Part 1, a generalized structural model},
  author = {R.L. Wershaw and D.J. Pinckney and S.E. Booker},
  year = {1977},
  url = {https://pubs.usgs.gov/publication/70163071},
  note = {Source identifier: 70163071}
}