@misc{indiciae6d072e1ebdd7,
  title = {Thermal effect in opal below room temperature.},
  author = {M J Buerger and G L Shoemaker},
  year = {1972},
  doi = {10.1073/pnas.69.11.3225},
  url = {https://pubmed.ncbi.nlm.nih.gov/16592025/},
  note = {Source identifier: 16592025}
}