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:In contrast to steam pretreatment, organosolv pretreatment results in the solubilisation of lignin that can be subsequently precipitated as a highly functional, enriched fraction with low carbohydrate contamination (Pan et al., 2006a).
Category: