Name Info Provider Link
subscription/membership/fee required Elsevier Science https://linkinghub.elsevier.com/retrieve/pii/S0024-3205(21)01178-4
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=34856208.ui