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:Furthermore, the Obwegeser-Dal Pont method delayed the recovery period of hypoesthesia of the lower lip and was associated with a higher incidence of lower lip hypoesthesia than the Obwegeser method (Hashiba et al., 2007; Takazakura et al., 2007).
Category: