meta-information about assertions

Hi all, 
i'm trying to merge rdf(more specifically OWL) graphs
from different sources using collaborative filtering
and trust related technologies. But my question is:
what is the proper way to encode a "meta assertion"
like "A says X about B", in order to deal with
contraddictory assertions?

Reification? Using SKOS? Something else?

Thank you in advance.


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