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 pressure could originate either from forces exerted by actin polymerization against the mitochondrial outer membrane (Korobova et al., 2013), or by myosin-II dimer mediated contraction of actin filaments lying between the ER and mitochondrial membranes (Hatch et al.
Category: