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:The 3 12.4 kb enhancer region (chr2: 19369662-19382088) was cloned into a nuclear mCherry reporter vector (with mCherry replacing EGFP in BgEGFP) to generate 12.4Ptf1amCherry or a lacZ reporter gene with the minimal promoter of the rat Ela1 gene to generate 12.4Ptf1a-lacZ (Masui et al., 2008).
Category: