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 cells greatly extend their length from 10 lm to 50 lm, the NAD(P)H oscillation grows dramatically in amplitude, superoxide production is increased, and, as a likely
consequence of superoxide production, cellular DNA is damaged (Kindzelskii and Petty 2000; Rosenspire et al. 2000, 2001).
Category: