Di Giorgio, D, “Optimal regularity and Fredholm properties of abstract parabolic operators in L-p spaces on the real line”, Proceedings of the London Mathematical Society, 91 (2005), 703
Latushkin, Y, “Fredholm differential operators with unbounded coefficients”, Journal of Differential Equations, 208:2 (2005), 388
Tyurin V.M., “On the Fredholm property of linear operators of elliptic type on $R^n$”, Differ. Equ., 40:2 (2004), 265–270
Latushkin Yu., Tomilov Yu., “Fredholm properties of evolution semigroups”, Illinois J. Math., 48:3 (2004), 999–1020
А. Г. Баскаков, “Об обратимости и фредгольмовости разностных операторов”, Матем. заметки, 67:6 (2000), 816–827 ; A. G. Baskakov, “Invertibility and the Fredholm property of difference operators”, Math. Notes, 67:6 (2000), 690–698