Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:Alternative provenance definitions are ontology-based and not specific to an execution technology: Provenir [20, 21], the Provenance Vocabulary [22], PASOA [23], OPMV [24], PML [25], and the Open Provenance Model [26].
Category: