Integral manifolds of impulsive differential equations. Bajnov, D.D.; Kostadinov, S.I.; Nguyen Van Minh; Nguyen Hong Thai; Zabrejko, P.P. — 1992 Journal of Applied Mathematics and Stochastic Analysis
Composing infinitely differentiable functions. J. Aööell; V.I. Nazarov; P.P. Zabrejko — 1991 Mathematische Zeitschrift