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:Rabbit polyclonal anti-P450 1A5 (Yip and Coulombe, 2006) and 3A37 (Rawal et al., 2010b) sera were raised against the peptide sequences “FLDFNKRFMKLLKTAVEE (amino acids 260–277)” and “SQKSDSDGKNSHKA (amino acids 278–291),” respectively by Genemed Synthesis (San Antonio, TX).
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