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:We propose to use a family of densities parametrized by functions belonging to a Reproducing Kernel Hilbert Space (RKHS) HY with positive semidefinite kernel k (Canu et al., 2006; Fukumizu, 2009; Sriperumbudur et al., 2017).
Category: