%0 Journal Article %A Grabowski, Piotr %T Comparison of direct and perturbation approaches to analysis of infinite-dimensional feedback control systems %J International Journal of Applied Mathematics and Computer Science %D 2021 %P 195-218 %V 31 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/item/IJAMCS_2021_31_2_a1/ %G en %F IJAMCS_2021_31_2_a1