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:…Lemos et al., 2015) at baseline, allowed for the division of the aMCI group according to an AD-alike pattern of impairment at baseline (Lemos et al., 2015), and was associated with the risk of conversion to AD in follow-up studies (Auriacombe et al., 2010; Petersen, 2007; Sarazin et al., 2010).
Category: