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:However, how frataxin interacts with the Fe-S cluster biosynthesis components remains unclear as direct one-to-one interactions with each component were reported (IscS [12,22], IscU/Isu1 [6,11,16] or ISD11/Isd11 [14,15]).
Category: