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:…(1994), Abramov and Zima (1996), Bronstein (2000), Schneider (2001, 2005c), simplifying the solutions by our advanced telescoping algorithms (Schneider, 2005a, 2008, 2010c, 2015) and taking the first 4 initial values of S(n) produces
S(n)= (−1)n n∑
i=1
(−3)i i
− (−1)n n∑
i=1
(−1)i i
+ 3n…
Category: