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:…form of plan recognition that focuses on inferring users’ goals without concern for identifying their plans or sub-plans, goal recognition models have been automatically acquired using statistical corpus-based approaches without the need for hand-authored plan libraries (Blaylock and Allen 2003).
Category: