However there are several ways links may be created between Calc documents.
My suggestion should be good for cell formula references to an external file, but you may also create links to named ranges in another document via Insert > Link to External Data, or to a sheet in another doc with Insert > Sheet from File.
Maybe the quickest way to check the details on these last 2 is to look for AreaLinks and SheetLinks using MRI or XRay.
In the case of named ranges through Link to External Data, the range name should show up in the Edit > Links dialog.
Hope this will helps you.