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:(Pottiaceae) exhibits a high level of genetic diversity; spore and propagule recruitment, the modality of vegetative reproduction and somatic mutations were suggested among the most probable causes of the high intra-specific molecular diversity observed (Spagnuolo et al. 2007).
Category: