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:The SNF1 gene (also known as CCR1 or CAT1) is essential for derepression of these genes [3–5], and sequencing and expression studies have revealed that SNF1 encodes a protein kinase [6].
Category: