<description value="Authentication mechanisms" /> <content value="complete" /> <count value="4" /> <concept> <code value="none" /> <display value="None" /> </concept> <concept> <code value="oauth2" /> <display value="OAuth2" /> </concept> <concept> <code value="bearer" /> <display value="Bearer token" /> </concept> <concept> <code value="basic" /> <display value="Basic authentication" /> </concept> </CodeSystem>