TY  - RPRT
TI  - What is a normal upper gastrointestinal tract?
AU  - D G Colin-Jones
AU  - P L Golding
PY  - 1991
DO  - 10.1136/bmj.302.6779.742
UR  - https://pubmed.ncbi.nlm.nih.gov/2021763/
ID  - 2021763
ER  -