The correct reference for Lidskii's original paper,
"Perturbation theory of non-conjugate operators", in Russian, is
The correct reference for the English translation is
Zh. Vychisl. Mat. i Mat. Fiz., volume 6 (1966), number 1 (January-February),
In our paper, we gave 1965 as the date of both papers, as well as the wrong
volume for the English translation. Part of the reason for the confusion
was that the English translation of Lidskii's paper gives an incorrect
citation of the Russian original, saying it was published in 1965.
U.S.S.R. Comput. Math. and Math. Phys. volume 6 (1966), number 1, p. 73-85.
Thanks to Sergey Savchenko for helping to clear this up.
A copy of the English version is here.