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:Our recent characterization of spike frequency adaptation intrinsic to VSMN led us to hypothesize that the duration of phase 2 should be positively correlated with increasing phase 3 frequency (Krans and Chapple 2005).
Category: