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:trachomatis genital infection can lead to serious sequelae among women, including pelvic inflammatory disease, tubal factor infertility, ectopic pregnancy and chronic pelvic pain [2] and, as other inflammatory STIs, can also facilitate the transmission of human immunodeficiency virus infection [3].
Category: