TY  - RPRT
TI  - Open access upper gastrointestinal endoscopy.
AU  - R V Heatley
PY  - 1993
DO  - 10.1136/bmj.306.6887.1224
UR  - https://pubmed.ncbi.nlm.nih.gov/8499851/
ID  - 8499851
ER  -