@misc{indiciaec54ef52b1c1d,
  title = {Physical observations of comets: Their composition, origin and evolution},
  author = {Cochran, Anita L. and Barker, Edwin S. and Cochran, William D.},
  year = {1991},
  url = {https://ntrs.nasa.gov/citations/19920003587},
  note = {Source identifier: 19920003587}
}