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:…sulfur cycling (Steudler and Peterson, 1984; Dacey et al., 1987) based on production of DMSP and DMS by benthic microalgae, macrophytes and macroinvertebrates (Otte et al., 2004; Van Alstyne and Puglisi, 2007), and MT production through anaerobic processes in the sediment (Lomans et al., 2002).
Category: