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:Previous studies established that caveolin-3 is recovered from neonatal rat cardiomyocyte cultures in light vesicular membranes, along with flotillin-1 and flotillin-2/ESA (19).
Category: