Name Info Provider Link
subscription/membership/fee required Atypon https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.111.084509?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub 0pubmed
Emergency Medical Services free resource MedlinePlus Health Information https://medlineplus.gov/emergencymedicalservices.html
subscription/membership/fee required Ovid Technologies, Inc. http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=22529065.ui