@misc{indiciae0a6c5339edcd,
  title = {Geology of the Arabian Peninsula; Aden Protectorate},
  author = {J.E. Greenwood and D. Bleackley},
  year = {1967},
  doi = {10.3133/pp560c},
  url = {https://pubs.usgs.gov/publication/pp560C},
  note = {Source identifier: pp560C}
}