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:Network dimensions showing the number of connections per neuron and the radius in the preceding layer from which 67% are received
the order of 100 spikes ⁄ s in the visual system (Rolls & Deco, 2002; Rolls, 2008b).
Category: