@misc{indiciae74235980c6cb,
  title = {Variation of strontium isotopes in tektites},
  author = {Pinson, W. H., Jr. and Schnetzler, C. C.},
  year = {1963},
  url = {https://ntrs.nasa.gov/citations/19640001430},
  note = {Source identifier: 19640001430}
}