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:*Author for correspondence (wallingford@austin.utexas.edu)
D E V E LO
P M
E N T
sufficient to disrupt core PCP asymmetry and result in a loss or reversal of structural polarity (Adler et al., 2000; Bastock et al., 2003; Strutt and Strutt, 2007; Tree et al., 2002).
Category: