Comments on a relationship

I have a situation in which i want to annotate the relationship
between multiple resources.  This seems like it would be a common
situation.

Specifically, i modeling copyright licensing.  Things (usually a file)
are governed by one or more legal licenses.  A relatively simple case
looks like

     <http://someproj.org/release-1.0.tar>
          dc:license [ a spdx:DisjunctiveLicenseSet;
                       spdx:licenses (  license:GPL2 license:Apache2 ) ].

I want to add to this some information about why i believe
<http://someproj.org/release-1.0.tar> is covered by each of those
licenses.  (Keeping in mind that the reasons for each are likely
different.)

I have thought of a couple of ways to handle this, but none that seem
compelling.  Are there standard patterns for how to model this
elegantly in RDF?

Peter Williams
<http://barelyenough.org>