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:Furthermore TGFβ is the only inhibitor of myogenesis that does not stimulate myoblast proliferation (Florini et al., 1986; Massague et al., 1986; Olson et al., 1986).
Category: