@misc{indiciae4ae6bf793a24,
  title = {The annulus vacuum sign.},
  author = {S P Bohrer},
  year = {1986},
  doi = {10.1007/bf00354067},
  url = {https://pubmed.ncbi.nlm.nih.gov/3704679/},
  note = {Source identifier: 3704679}
}