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:…and new
Frontiers in Cellular Neuroscience www.frontiersin.org December 2014 | Volume 8 | Article 433 | 5
ideas regarding cell degeneration in ALS including, intracellular calcium dysregulation, mitochondria, oxidative stress, and possibly excitotoxicity (Martin, 2010a,b; Reddy and Reddy, 2011).
Category: