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:High differentiation of populations in M. decussata is similar to those of some long-lived, wind-pollinated species with fragmented distributions (Huang et al. 2002; Petit et al. 2005;
Jaramillo-Correa et al. 2006; Provan et al. 2007).
Category: