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:Quality of the analyzed RNA samples was evaluated using electropherograms obtained from microcapillary electrophoresis
microcapillary electrophoretic RNA separation (by Agilent 2100 Bioanalyzer) showed higher sensitivity for the assessment of RNA quality (Schroeder et al. 2006).
Category: