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:rPhl p 6251, a fusion protein [16] consisting of the four major timothy grass pollen allergens (Phl p 1, Phl p 2, Phl p 5, Phl p 6), as well as recombinant allergens (rBet v 1, rPhl p 1, rPhl p 2, rPhl p 5, rPhl p 6, rPhl p 12) were obtained from Biomay (Vienna, Austria).
Category: