@misc{indiciaed67be73b7b9e,
  title = {LED's: convenient, inexpensive sources for visual experimentation--a modified circuit.},
  author = {A B Alden},
  year = {1983},
  doi = {10.1016/0042-6989(83)90049-4},
  url = {https://pubmed.ncbi.nlm.nih.gov/6868377/},
  note = {Source identifier: 6868377}
}