Name Info Provider Link
B Vitamins free resource MedlinePlus Health Information https://medlineplus.gov/bvitamins.html
subscription/membership/fee required Nature Publishing Group https://doi.org/10.1038/sj.ejcn.1602972
subscription/membership/fee required Ovid Technologies, Inc. http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=18091765.ui