Name Info Provider Link
subscription/membership/fee required Atypon https://www.acpjournals.org/doi/10.7326/0003-4819-122-5-199503010-00006?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub 0pubmed
Managed Care free resource MedlinePlus Health Information https://medlineplus.gov/managedcare.html
subscription/membership/fee required Ovid Technologies, Inc. http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=7847647.ui