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:These criteria were intentionally lenient to prevent discarding any viable results; in actuality, the real amplitudes of crustal plateau short-wavelength folds are likely on the order of 100 m [e.g., Ghent and Hansen, 1999].
Category: