CSS

[x] Update to the latest version of the toolset and replace core.css and se.css with the latest versions from the toolset (running lint will show you the location of the file you need to copy).
[x] <i>Children’s Tales</i> should get book title semantics (I think this might be referring to the Grimms’ fairy tales?).
[x] There are some cases where you have a foreign-language title that is missing either the language or title semantics:
Zarevo needs xml:lang="ru-Latn" semantics.
Marche Funèbre should also get epub:type="se:name.music" semantics.
I am not entirely sure what Le Phare is exactly, but epub:type="se:name.publication.magazine" seems reasonable enough.
[x] soviets can be deitalicized since it is in Merriam-Webster.

Metadata

[x] Up to you, but it may be interesting to link Roads to Freedom, My Disillusionment in Russia, or The Bolshevik Myth in the long description since they cover similar themes and this might help readers find relevant material.

3bb844f18214c60ecae9185e70c32c5d56df4da7: The changes are fine, but in the future it is better to break up edits like this into one commit per name, with the name in the commit message, to make it easier to review and revert if necessary.
It’s not a problem per se, but we generally don’t need to add semantics like <time> tags if they aren’t relevant to either the formatting of the text or the pronunciation (for screereaders).