Name	Info	Provider	Link
	subscription/membership/fee required	Atypon	https://econtent.hogrefe.com/doi/10.1024/0300-9831/a000769?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub 0pubmed
Vitamin A	free resource	MedlinePlus Health Information	https://medlineplus.gov/vitamina.html
	free resource	IMR Press	https://www.imrpress.com/journal/IJVNR/93/6/10.1024/0300-9831/a000769