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 Feasible-Infeasible Two-Population Genetic Algorithm (FI2PopGA) [3, 4, 5, 6, 7] retains infeasible solutions whose evolutionary selection is based on fitness measured as distance from feasibility.
Category: