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:pelagicus only covers the Arctic Ocean and the sub-polar Northern Hemisphere (McIntyre and Bé, 1967; McIntyre et al., 1970), with a particular prevalence in the sub-polar North Atlantic (Milliman, 1980; Tarran et al.
Category: