@misc{indiciae47dd428267bd,
  title = {Copper in human subgingival calculus.},
  author = {M Knuuttila and R Lappalainen and M Rajala and H Markkanen},
  year = {1983},
  doi = {10.1111/j.1600-0722.1983.tb00789.x},
  url = {https://pubmed.ncbi.nlm.nih.gov/6574580/},
  note = {Source identifier: 6574580}
}