When Acrolinx first checks a document the Core Platform assigns it a content reference. Documents with the same content reference are treated as the same document.
The content reference comes from the file path or source to the document's location when it’s first checked, the document name and the author. If one or more of these parameters changes, the document receives a new content reference and is treated as a new document.
You can see the Source of a document in the Administrative Information of your Scorecard.