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:[5,6,13,14] The abdominal superficial venous dominance is one of the most extended and accepted (but not proved) hypothesis for explaining the diffuse congestion as a large diameter SIEV may denote dominance over the deep venous system.[6] Blondeel et al.
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