Barreira, Luis, Meng Fan, Claudià Valls, and Jimin Zhang. 2011. “Robustness of Nonuniform Polynomial Dichotomies for Difference Equations”. Topological Methods in Nonlinear Analysis 37 (2):357-76. https://apcz.umk.pl/TMNA/article/view/TMNA.2011.018.