Name Info Provider Link
COVID-19 Vaccines free resource MedlinePlus Health Information https://medlineplus.gov/covid19vaccines.html
subscription/membership/fee required Ovid Technologies, Inc. http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=34309623.ui
free resource PubMed Central https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/34309623/
free resource Europe PubMed Central https://europepmc.org/abstract/MED/34309623
subscription/membership/fee required Silverchair Information Systems https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/10.1001/jamainternmed.2021.3779