| Name | Info | Provider | Link |
|---|---|---|---|
| Calcium | free resource | MedlinePlus Health Information | https://medlineplus.gov/calcium.html |
| subscription/membership/fee required | Ovid Technologies, Inc. | http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=18549509.ui | |
| subscription/membership/fee required | Cambridge University Press | https://www.cambridge.org/core/product/identifier/S0007114508993533/type/journal_article |