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:Comparison of Ptf1a regulation in the CNS and pancreas These findings parallel those recently reported in the pancreas, where the 2.3 kb 5 element is also active (Masui et al., 2008).
Category: