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:Mck mutants resulted in a low-level viremia, poor dissemination to salivary glands, and reduced MCMV-associated inflammation in livers (Fleming et al., 1999; Saederup et al., 1999).
Category: