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:…BG.
Nestin is a forerunner to GFaP in the cytoskeleton during ontogenesis of the nervous system (hockfield and McKay 1985; Marvin et al. 1998; Kalman and ajtai 2001; Mudo et al. 2009) and in the cerebellum (Yamada and Watanabe 2002) as well. these articles described that
1 3
nestin first…
Category: