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:Our results for regulation of PR protein expression are consistent with other reports, which demonstrate cyclic changes in PR proteins in human (52, 53) and rat (18, 50) Fallopian tubes as well as human (39, 43, 75) and rat (27) uteri.
Category: