@misc{indiciae87ce37729ef1,
  title = {Gastroduodenal endoscopy.},
  author = {W L Peterson},
  year = {1973},
  doi = {10.1001/archsurg.1973.01350200208044},
  url = {https://pubmed.ncbi.nlm.nih.gov/4541666/},
  note = {Source identifier: 4541666}
}