Name	Info	Provider	Link
	subscription/membership/fee required	Elsevier Science	https://linkinghub.elsevier.com/retrieve/pii/S0009-8981(21)00078-4
Vitamin D	free resource	MedlinePlus Health Information	https://medlineplus.gov/vitamind.html
	free resource	PubMed Central	https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/33713690/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/33713690
	free resource	scite Smart Citations	https://scite.ai/reports/33713690