Effect of nonlinear perturbations on second order linear nonoscillatory differential equations.
Error estimation for perturbed systems.
Estimates for the Cauchy matrix of perturbed linear impulsive equation.
Estimates of the lower exponent of a two-dimensional linear system under Perron perturbations.
Exponential estimates on the one-dimensional Schroedinger equation with bounded analytic potential
Exponential stability of nonlinear time-varying differential equations and applications.
Extrait d'une Lettre à M. Hermite, relative à l'application des fonctions elliptiques à la théorie des perturbations.