@misc{indiciae06676342d506,
  title = {An automatic contact-counter for recording object play.},
  author = {P H Martin and D M Unwin},
  year = {1985},
  doi = {10.1016/0031-9384(85)90356-7},
  url = {https://pubmed.ncbi.nlm.nih.gov/4070403/},
  note = {Source identifier: 4070403}
}