Representation of consecutive layers of interpretation. Consecutive layers of interpretation can be represented as assertions the subject of which is about other assertions. A) CB's assertion that 'Tate and co-workers assert that assay-1 was a gamma-GHS assay in their 1972 report' is represented as an assertion instance linked to a proposition instance whose named graph representation relates the assertion instance A10 to the Tate 1972 report via the is_assertion_made_in property. B) TriG representation of the graph shown in A. In combination with the RDF dataset shown in Figure 5C this is an example of a named graph referencing a named graph via the corresponding assertion> and proposition instances. Color code as in figure 1.