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:Similar data were found by Nir et al. (1994a) and Nir et al. (1995), who reported that the pelleting process reduced proventriculus and gizzard weight, as well as their contents, without changing the pH of these segments.
Category: