| Name | Info | Provider | Link |
|---|---|---|---|
| Gastrointestinal Bleeding | free resource | MedlinePlus Health Information | https://medlineplus.gov/gastrointestinalbleeding.html |
| subscription/membership/fee required | Ovid Technologies, Inc. | http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=18696215.ui | |
| subscription/membership/fee required | Springer | https://doi.org/10.1007/s11239-008-0263-5 |