@misc{indiciaeec0ee2fa3219,
  title = {The variations in visual threshold measurement.},
  author = {P E Hallett},
  year = {1969},
  doi = {10.1113/jphysiol.1969.sp008818},
  url = {https://pubmed.ncbi.nlm.nih.gov/5784294/},
  note = {Source identifier: 5784294}
}