| Name | Info | Provider | Link |
|---|---|---|---|
| subscription/membership/fee required | Ediciones Doyma, S.L. | http://www.elsevier.es/en/linksolver/ft/pii/S0210-5705(21)00229-6 | |
| subscription/membership/fee required | Elsevier Science | https://linkinghub.elsevier.com/retrieve/pii/S0210-5705(21)00229-6 | |
| Peptic Ulcer | free resource | MedlinePlus Health Information | https://medlineplus.gov/pepticulcer.html |