@misc{indiciaec509547c80d9,
  title = {Petrologic characteristics of the 1982 and pre-1982 eruptive products of El Chichon volcano, Chiapas, Mexico},
  author = {J. J. McGee and R.I. Tilling and W. A. Duffield},
  year = {1987},
  doi = {10.22201/igeof.00167169p.1987.26.1.1190},
  url = {https://pubs.usgs.gov/publication/70015239},
  note = {Source identifier: 70015239}
}