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:The concentration of glucose in MS loC is the concentration used to produce C-starved cells (Spector & Cubitt, 1992; O’Neal et al., 1994; Kenyon et al., 2002) and provides sufficient glucose to support growth for 3–4 generations before being exhausted.
Category: