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:There were two measures of WMC: the reading span task
 (Daneman & Carpenter, 1980) and the spatial span task (Miyake et al., 2001, Shah & Miyake, 1996) (see Figure 1 for illustration of tasks).
Category: