TY  - RPRT
TI  - Overcoming sphincteric resistance during endoscopy.
AU  - M Freud
AU  - A Weissler
PY  - 1977
DO  - 10.1056/nejm197702032960519
UR  - https://pubmed.ncbi.nlm.nih.gov/831117/
ID  - 831117
ER  -