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:…paralysis and show a very prominent lower motor neuron disease (Gurney et al., 1994; Bendotti et al., 2001; Martin et al., 2007), the details of the cellular and molecular pathology appear to be distinct from that seen in human ALS (Martin, 1999, 2010a; Martin and Liu, 2004; Martin et al., 2007).
Category: