Name Info Provider Link
subscription/membership/fee required Atypon https://www.ahajournals.org/doi/10.1161/01.hyp.27.6.1224?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub 0pubmed
subscription/membership/fee required Ovid Technologies, Inc. http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=8641728.ui