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 is regarded as the onset of the average Si-O coordination number increasing from 6 to 6+ (“6+-fold (Si)” in this figure) in each glass (see Murakami and Bass 2010, 2011).
Category: