Get Linked Work Item for DOORS Change Set

 I can easily get (from the Work Item query in the EWM REST API) a DOORS change set that's linked to a work item. I need to go the other direction but can't figure it out. Is there a request to get from a DOORS change set URL to see the links? I can see in the dev tools that DOORS itself uses an internal API and retrieves the 'derivedLinks?changesets=" the change set URL... and I even added the 'private header', but now am getting a bad request.