Name Info Provider Link
free resource Elsevier Science https://linkinghub.elsevier.com/retrieve/pii/S1743-9191(15)00214-9
Endoscopy free resource MedlinePlus Health Information https://medlineplus.gov/endoscopy.html
subscription/membership/fee required Ovid Technologies, Inc. http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=25981308.ui
subscription/membership/fee required ClinicalKey https://www.clinicalkey.com/content/playBy/pii?v=S1743-9191(15)00214-9