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:…studies show that colonies of Aurelia spp. polyps are mainly distributed on artificial constructions off the coasts of Japan, the UK, France and the Mediterranean (Miyake et al., 2002; Ishii & Katsukoshi, 2010; Duarte et al., 2012; Malej et al., 2012; Marques et al., 2015; Vodopivec et al., 2017).
Category: