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:Our results further confirm previous findings on the differential regulatory mechanisms for Hoxa3 and Hoxb3 expression in r5 and r6 by kreisler (Manzanares et al., 1997, 1999a,b, 2001).
Category: