@misc{indiciae913c5ab15eea,
  title = {Upper intestinal endoscopy.},
  author = {M L Clark},
  year = {1985},
  doi = {10.1016/s0140-6736(85)92158-0},
  url = {https://pubmed.ncbi.nlm.nih.gov/2857959/},
  note = {Source identifier: 2857959}
}