RefWorks is a member of InCommon and OpenAthens.
EntityID = https://shibboleth.refworks.proquest.com/shibboleth/sp
If using eduPersonPrincipalName, release "eppn".
If using eduPersonTargetedID, release "persistent-id" or "oid-targeted-id". Other attributes would be needed if using scope (sub institution level access) or affiliation (user roles).
Metadata can be downloaded from: https://shibboleth.refworks.proquest.com/Shibboleth.sso/Metadata
Note entityId=https://shibboleth.refworks.proquest.com/shibboleth/sp in the file.