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:17 CVL1/CVP2 In Arabidopsis thaliana, PtdIns(4,5)P2 is dephosphorylated by the 5TPases COTYLEDON VASCULAR PATTERN 2 (CVP2) and CVP2 LIKE 1 (CVL1) (Carland and Nelson, 2009; Carland and Nelson, 2004).
Category: