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:Currently, one of the most frequently utilized approaches to regenerate large bone defects relies on the placement of scaffolds under the premise that space maintenance will occur in tandem with new bone formation within the scaffold-filled defect [4, 10, 22].
Category: