@misc{indiciae36cf54928b6e,
  title = {Upper gastrointestinal endoscopy.},
  author = {W G Guilford},
  year = {1990},
  doi = {10.1016/s0195-5616(90)50301-0},
  url = {https://pubmed.ncbi.nlm.nih.gov/2238368/},
  note = {Source identifier: 2238368}
}