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:Here, we investigated the possibility that SPARC (osteonectin ⁄BM-40 ⁄ culture-shock protein) (Termine et al., 1981; Kopp et al., 1992; Tiruppathi et al., 1996; Blazejewski et al., 1997), a glycoprotein that has been shown to
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