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:Arpp/Ankrd2 has been found to be induced in denervated muscles (Tsukamoto et al. 2002) and in muscles chronically immobilized in a stretched position (Kemp et al. 2000).
Category: