@misc{indiciaeed72cac93c5a,
  title = {Possible Late Middle Ordovician organic carbon isotope excursion: Evidence from Ordovician oils and hydrocarbon source rocks, mid-continent and east-central United States},
  author = {Joseph R. Hatch and Stephen R. Jacobson and Brian J. Witzke and J. Bruno Risatti and Donald E. Anders and W. Lynn Watney and K. David Newell and April K. Vuletich},
  year = {1987},
  doi = {10.1306/703c8074-1707-11d7-8645000102c1865d},
  url = {https://pubs.usgs.gov/publication/70014137},
  note = {Source identifier: 70014137}
}