Name Info Provider Link
subscription/membership/fee required Atypon https://econtent.hogrefe.com/doi/10.1024/0300-9831.69.4.243?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/69/4/10.1024/0300-9831.69.4.243