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:In addition, a precise supracondylar osteotomy with the desired angle is a technically demanding procedure and placement of a plate requires a rather large incision [4, 10, 17, 19, 23, 30].
Category: