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:Unlike many previous studies (Landry et al. 2005, McManus et al. 2010, Malone and Michalak 2008, Renaut et al. 2009, Bell et al. 2013, Coolon et al. 2014), we found that misexpression was rare among the genes we measured in hybrid zebra finches.
Category: