You may find settlement documents appear as source documents for other accounting documents. You can use the DRB to determine the links from settlement documents to the dependent accounting documents.
From the point of view of the settlement documents there are no additional prerequisites for determining links. It is immaterial whether the settlement document has already been archived. The link from and to the settlement document is always determined by the dependent document, as that is where the link from and to the source document is always determined. Which prerequisites apply from the point of view of these documents you can obtain from the relevant documentation:
Linking Source Document to Cost Accounting DocumentLinking Cost Accounting Document to Source Document
Determining Links (FI-SL)
Costing-Based Profitability Analysis in the DRB (CO-PA)
Determining Links (EC-PCA)