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:On the other hand, Leyden et al. (1981) demonstrated that the prevalence of lipophilic diphtheroids, which could be related to the typical pungent ‘‘apocrine’’ odor, was lower in female axilla than in male axilla.
Category: