Hi Rosevidney1,
Those pilots note you list are the sort of thing that are sold on the stalls at Russian air shows and aircraft enthusiast gatherings. There is, or certainly was, a large monthly meeting in central Moscow once a month at which tables and tables of aircraft books and plastic models were sold.
There are a number of Ppruners who post from Russia, who it could be worth PMing in case they have any suitable contacts.
Another source would be to make contact with George Pick tours who run regular trips to the Moscow Airshow (MAKS) in Zhukovski as well as others in Eastern Europe. There are a number of enthusiasts who go regularly who could look at the stalls, or may even have their own Russian contacts or know the traders who attend.
A wanted advert in the classifieds in the likes of Flypast or Aeroplane Monthly will find its way to all corners of the world (in case the English notes you are after are outside of Russia).
Krilia Rodiny (Wings of the Motherland) is an long established Russian Language magazine which would put you in touch with Russian enthusiasts.
Here is a list of other current and defunct Russian aircraft magazines.
Russian & Belorussian Aircraft Magazines
There are also plenty of Russian aviation forums on which you could post a wanted ad. Make sure you have the full suite of anti-virus and anti-malware software before browsing Russian sites though.
Foxbat AVIa
: - ScaleModels.ru
Beware that some Russians have the idea that Western streets are paved with gold, and they may ask silly money for the manuals. You also need to be sure that you will be getting something for your money. It may be a good idea to say 'up to $xx paid for Pilots notes in English, paid on receipt', and get photos of the manual sent before agreeing to the deal.