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:This interference model has been studied recently by a number of authors; for example, see Jain et al [11], Hamdaoui and Ramanathan [10], and Gupta, Musacchio and Walrand [6].
Category: