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:Increasing evidence indicates that cell cycle activation (CCA) is involved in the pathophysiology of both acute and chronic neurodegenerative disorders as follows: cerebral ischemia [3], brain and spinal cord injury [4–6], Alzheimer’s disease (AD) [7, 8], Parkinson’s disease [9, 10], and amyotrophic lateral sclerosis [11, 12].
Category: