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:Myogenin, which is transcriptionally induced upon denerva-
tion by an HDAC4-dependent mechanism (Cohen et al., 2007),
was recently reported to activate MuRF1 and atrogin-1 tran-
scription and muscle atrophy (Moresi et al., 2010).
Category: