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:Serum separated from blood of each animal and analyzed the biochemical parameters such as, Glycosylated hemoglobin [13], Plasma insulin (Boehringer‚ÄìMannheim kit), total protein [14], SGOT [15], SGPT [15] and ALP [16].
Category: