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:They were performed in different countries (Gambia [24], Iraq [21], UK [25], Lebanon [26], Turkey [27,28,29,34], Iran [30,32,33,35], and UAE [31]) (Table 2).
Category: