@misc{indiciaeae2e861a078a,
  title = {Selected annotated bibliography on asphalt-bearing rocks of the United States and Canada, to 1970},
  author = {Marjorie C. Mullens and Albert Eugene Roberts},
  year = {1972},
  doi = {10.3133/b1352},
  url = {https://pubs.usgs.gov/publication/b1352},
  note = {Source identifier: b1352}
}