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:2014/10/16 file: den_leon_bernoulli_final.tex date: June 3, 2015
Anh, Leonenko and Shieh (2008a,b, 2009a,b, 2010) considered multifractal products of stochastic processes as defined in Kahane (1985), Kahane (1987) and Mannersalo et al (2002).
Category: