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:Following the state-of-the-art technique for exploratory data analysis (Baroni et al., 2014), we decided to opt for unsupervised clustering. The chosen normalized spectral clustering algorithm proposed by Ng et al. (2001) has been effectively applied to various lexical acquisition tasks (e.g. Shutova et al. (2016); Xu & Ke (2016); Sun & Korhonen (2009)).
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