@misc{indiciae980c5b21c195,
  title = {Classification and nomenclature of rock units},
  author = {G. H. Ashley and M.G. Cheney and J.J. Galloway and C.N. Gould and C.J. Hares and B.F. Howell and A.I. Levorsen and H. D. Miser and R.C. Moore and J.B. Reeside and W.W. Rubey and T. W. Stanton and G. W. Stose and W.H. Twenhofel},
  year = {1933},
  doi = {10.1130/gsab-44-423},
  url = {https://pubs.usgs.gov/publication/70207448},
  note = {Source identifier: 70207448}
}