@misc{indiciae6744c3cedbd7,
  title = {Vibrating umbilicus.},
  author = {D Jackson and B Mayou},
  year = {1973},
  doi = {10.1136/bmj.2.5869.780-c},
  url = {https://pubmed.ncbi.nlm.nih.gov/4718338/},
  note = {Source identifier: 4718338}
}