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:Pk also physically interacts with Vang, and this interaction leads to the clustering of Vang on the opposite side of the cell (Bastock et al., 2003; Jenny et al., 2003; Strutt et al., 2011).
Category: