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:We observed an overall incidence of hearing loss of 25.8% which is partially in accordance with other studies (Olgun et al.,2016, Laurell and Jungnelius,1990; Yancey et al., 2012).
Category: