@misc{indiciaececed53b3a16,
  title = {LEDs: convenient, inexpensive sources for visual experimentation.},
  author = {R W Nygaard and T E Frumkes},
  year = {1982},
  doi = {10.1016/0042-6989(82)90190-0},
  url = {https://pubmed.ncbi.nlm.nih.gov/7112942/},
  note = {Source identifier: 7112942}
}