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 study on the graft transmission of phloem proteins in interspecific and intergeneric heterografts in the Cucurbitaceae family suggested that the direction of phloem protein translocation depended on the scion/rootstock combination [43].
Category: