@misc{indiciae1b726ccecff3,
  title = {The plastic cone. A new device for marking microscopic fields.},
  author = {W P HOREN and W G STRAUSS},
  year = {1961},
  doi = {10.1093/ajcp/36.4.339},
  url = {https://pubmed.ncbi.nlm.nih.gov/14448880/},
  note = {Source identifier: 14448880}
}