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:of Rosenstein et al. (1993). Using the model free method of Rosenstein et al. (1993), the three treatments were all found to result in slightly positive LEs, but the results were deemed inconclusive given the small sample size (4 replicates of 18 generations) and the sensitivity of the method to any kind of stochastic noise (demographic or environmental).
Category: