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:Several plans to unlock subglacial lakes exist ( Siegert et al. , 2004; Inman, 2005; Siegert et al. , 2007; Schiermeier , 2008; Woodward et al. , 2009) and valuable knowledge will be available as soon as direct samples of subglacial water and sediments are taken.
Category: