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:Various methods, including arthrodesis, hip transposition, osteoarticular allograft/autograft and prosthetic implantation, have been used for hemipelvic reconstruction after peri-acetabular tumour resection [5–17].
Category: