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:Based on their ability to monitor the dielectric characteristics of the surroundings separately from hydrogen bonding [18], several 3HC-based probes were designed to quantify the local water concentration at selected positions of biomolecules [17], opening new possibilities in the investigation of biomolecular interactions [19, 20].
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