@misc{indiciaebcd1a425eab7,
  title = {Some natural variations in the relative abundance of copper isotopes},
  author = {E. C. Walker and F. Cuttitta and F. E. Senftle},
  year = {1958},
  doi = {10.1016/0016-7037(58)90056-5},
  url = {https://pubs.usgs.gov/publication/70010647},
  note = {Source identifier: 70010647}
}