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 contrast to that observed for InlA-mediated uptake of L. monocytogenes (Bonazzi and Cossart, 2006), inhibition of caveolin-1 had little effect on rOmpB-mediated invasion of HeLa cells.
Category: