@misc{indiciaecbb5d1b57889,
  title = {Activity level: a comparison between actometer scores and observer ratings.},
  author = {T M Stevens and M J Kupst and B G Suran and J L Schulman},
  year = {1978},
  doi = {10.1007/bf00919122},
  url = {https://pubmed.ncbi.nlm.nih.gov/670584/},
  note = {Source identifier: 670584}
}