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 comparable to results obtained by GonzaÃÅlez Benito et al. (1997), who conducted laboratory batch tests to determine the ability of Trametes versicolor to treat molasses-based distillery wastewater.
Category: