TY  - RPRT
TI  - Letter: Upper gastrointestinal endoscopy.
AU  - P M Smith
PY  - 1974
DO  - 10.1016/s0140-6736(74)91392-0
UR  - https://pubmed.ncbi.nlm.nih.gov/4134445/
ID  - 4134445
ER  -