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:Chlorhexidine has previously demonstrated an antibacterial spectrum that includes most of the microorganisms present in the oral cavity, such as Gram-positive and Gram-negative bacteria, bacterial spores, lipophilic viruses, yeasts and dermatophytes [7].
Category: