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:Experimental as well as numerical methods were used to analyse the scenario of an RF exposed Petri dish (35 mm diameter) within a waveguide-based exposure setup at 1800 MHz (sXc-1800, Schuderer et al 2004b).
Category: