@misc{indiciae356a252b4af6,
  title = {A modern frequency and phase indicating toposcope.},
  author = {H W Shipton and G L Armstrong},
  year = {1981},
  doi = {10.1016/0013-4694(81)91442-5},
  url = {https://pubmed.ncbi.nlm.nih.gov/6172267/},
  note = {Source identifier: 6172267}
}