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:It should be noted that a WURS cut-off score of 46 or higher can discriminate individuals with a history of childhood attention-deficit/ hyperactivity disorder (Kafka & Prentky, 1998; Roy-Byrne et al., 1997; Ward et al., 1993; Wender, 1995).
Category: