difference equation - SERP Analysis

https://math.dartmouth.edu/opencalc2/dcsbook/c1pdf/sec14.pdf

https://math.libretexts.org/Bookshelves/Analysis/Supplemental_Modules_(Analysis)/Ordinary_Differential_Equations/2%253A_First_Order_Differential_Equations/2.1%253A_Difference_Equations

https://en.wikipedia.org/wiki/Finite_difference

https://theengineeringmaths.com/wp-content/uploads/2017/09/difference-equations.pdf

https://mathworld.wolfram.com/DifferenceEquation.html

https://www.youtube.com/watch%3Fv%3DUlOu-jmGqas

https://www.dsprelated.com/freebooks/filters/Difference_Equation_I.html

https://www.sciencedirect.com/topics/mathematics/difference-equation

https://statmath.wu.ac.at/courses/MEC_MM/download/handouts/MMEcon-handouts-18-Difference_Equation.pdf

https://www.rand.org/content/dam/rand/pubs/reports/2006/R374.pdf