| Name | Info | Provider | Link |
|---|---|---|---|
| Vitamin D | free resource | MedlinePlus Health Information | https://medlineplus.gov/vitamind.html |
| subscription/membership/fee required | Ovid Technologies, Inc. | http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=20135096.ui | |
| subscription/membership/fee required | Springer | https://doi.org/10.1007/s00198-009-1158-9 |