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:Existing applications of neural meanfield models to anesthesiainduced changes in spontaneous EEG rhythmsmostly focused on understanding the dynamical mechanisms underlying bi-phasic responses (Bojak and Liley, 2005; Hutt and Longtin, 2010; Steyn-Ross et al., 1999).
Category: