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:have previously suggested that the TBEV genome of Toro 2003, with the (A)3C(A)6 poly(A) tract is the typical W-TBEV detected within the questing ticks, as that sequence came directly from the tick total RNA [30]; however, here we demonstrate that the shorter TBEV variants indeed also exist in nature within the questing ticks.
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