Name Info Provider Link
subscription/membership/fee required Elsevier Science https://linkinghub.elsevier.com/retrieve/pii/S0022-4804(19)30530-X
Vitamin D Deficiency free resource MedlinePlus Health Information https://medlineplus.gov/vitaminddeficiency.html
subscription/membership/fee required ClinicalKey https://www.clinicalkey.com/content/playBy/pii?v=S0022-4804(19)30530-X