@misc{indiciaef118b2962887,
  title = {Classification of variable material.},
  author = {H S CONRAD},
  year = {1953},
  doi = {10.1126/science.117.3040.364-a},
  url = {https://pubmed.ncbi.nlm.nih.gov/13048684/},
  note = {Source identifier: 13048684}
}