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:Finally we show that, from a single input image, we are able to generate the basis images employed by a number of illumination-insensitive recognition algorithms (Illumination Cone [8], Harmonic Images [2] and Nine Points of Light[11]).
Category: