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:Some STEC strains are regarded as emerging food-borne pathogens of significant clinical and public health concern (Kawano et al., 2012), which are the leading cause of several human illnesses ranging from symptom-free carriage to hemorrhagic colitis and even life-threatening sequelae such as hemolytic uremic syndrome (HUS) (Bandyopadhyay et al.
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