@misc{indiciae081fa600a2ee,
  title = {'Butterfly' sign.},
  author = {P Plantin and P Delaire and B Sassolas and G Guillet},
  year = {1989},
  doi = {10.1016/s0190-9622(89)80281-6},
  url = {https://pubmed.ncbi.nlm.nih.gov/2808803/},
  note = {Source identifier: 2808803}
}