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:4% of the cells contained in human ADH/dysplasia [29], and in 59% of the cells within human DCISs at Penylvania State U niersity on Feruary 3, 2013 http://carcfordjournals.
Category: