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:Intensive efforts to reduce tobacco use have also been conducted by the government and public health professionals, leading to the implementation of strong and effective tobacco control policies and measures, such as tobacco tax increases, media campaigns, and ratification of Framework Convention on Tobacco Control [3].
Category: