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:Unlike in (Sriperumbudur et al., 2017; Sutherland et al., 2017), the score function Ĵ(T ) cannot be used as a metric to compare different factorizations of the estimated distribution, as it is dependent on the specific factorization of the joint distribution.
Category: