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:, Smack [18], SeaHorn [11], cbmc [7], esbmc [10], and Cascade [22]) to transforming an imperative program to a side-effect-free form is to map each pointer p to a symbolic memory region Mp using a pointer analysis.
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