Invariance principle for stability in the sense of Lyapunov

Question

On Wikipedia this article about the invariance principle and article states that

The general result was independently discovered by J.P. LaSalle (then at RIAS) and N.N. Krasovskii, who published in 1960 and 1959 respectively. While LaSalle was the first author in the West to publish the general theorem in 1960, a special case of the theorem was in communicated in 1952 by Barbashin and Krasovskii, followed by a publication of the general result in 1959 by Krasovskii.

Hence, I am wondering if this claim is correct (references please I couldn't find the reference form 1959).

Answer 1

MR0106313 Krasovskiĭ, N. N. {\cyr Nekotorye zadachi teorii ustoĭchivosti dvizheniya.} (Russian) [Certain problems in the theory of stability of motion] Gosudarstv. Izdat. Fiz.-Mat. Lit., Moscow 1959 211 pp.

MR0052616 Barbašin, E. A.; Krasovskiĭ, N. N. On stability of motion in the large. (Russian) Doklady Akad. Nauk SSSR (N.S.) 86, (1952). 453-456.