@misc{indiciaede1997976bb2,
  title = {Extractable organic matter in Precambrian cherts},
  author = {Kaplan, I. R. and Schopf, J. W. and Smith, J. W.},
  year = {1970},
  url = {https://ntrs.nasa.gov/citations/19700059853},
  note = {Source identifier: 19700059853}
}