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:Olfactory bulb odorant ORFs These results are consistent with previously reported studies of mitral‚Äìtufted cell responses to odorants differing in carbon chain length (Imamura et al., 1992).
Category: