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:Several studies described the positive correlation between the expression of mature miR-99a and primary miR-99a and that of their host gene C21orf34/LINC00478 in liver and prostate cancer tissues, suggesting the possible cotranscription of miR-99a with C21orf34 [10,47].
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