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 consistent with studies of Askaer et al. (2011); Mahmood and Strack (2011) and Herbst et al. (2013) who demonstrated the importance of soil temperature in controlling microbial activities when conditions are favorable for CH4 production (i.e., at high GWL).
Category: