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:Our choice of studying CFI in higher detail is based on several considerations: (i) CFI represents one of the hallmarks of metazoan CPA composition, (ii) it affects APA reactions in vitro [28,29], (iii) its molecular structure is well understood in mammals [20], and (iv) one of its members, CFI25, was shown to be involved in human pathologies including cancer and tumorigenesis [30].
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