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:Indeed, sex-specific molecular genetic markers have been developed in various organisms with heterogametic sex determination systems (e.g. Carmichael et  al. 2013; Devlin et  al. 2001; Felip et  al. 2005; Fowler and Buonaccorsi 2016; Gamble et al. 2015; Gamble and Zarkower 2014; Griffiths and Orr 1999; Griffiths and Tiwari 1993; Griffiths et al. 1992; Kafkas et al. 2015).
Category: