| Name | Info | Provider | Link |
|---|---|---|---|
| Vitamin A | free resource | MedlinePlus Health Information | https://medlineplus.gov/vitamina.html |
| subscription/membership/fee required | Ovid Technologies, Inc. | http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=33048363.ui | |
| subscription/membership/fee required | Wiley | https://doi.org/10.1111/ics.12669 |