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:Although the study of heat transfer in magmatic systems has a venerable history (e.g. Ingersoll et al., 1954; Shaw, 1965; Jaeger, 1968; Spera, 1979; Carrigan, 1988; Huppert & Sparks, 1988; Bergantz, 1989; Marsh, 1989), the explicit connection between heat transfer and the trace element and isotopic…
Category: