Name	Info	Provider	Link
	free resource	BioMed Central	https://trialsjournal.biomedcentral.com/articles/10.1186/s13063-019-3241-7
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/30832722/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/30832722