https://dissexpress.proquest.com/dxweb/results.html?QryTxt=&By=Oleg+Timofeyev&Title=&pubnum= – the only doctoral thesis on the Russian Guitar. You will have to pay a fee for the printing, but it is well worth it! 600 pages of fascinating facts, and a very entertaining read.
http://The Guitar of the Czars a new English summary redaction by Marco Bazzotti – an interesting history article.
http://sevenstring.ru/index.php/katalog-not/avtory-po-periodam/rannij-dorevolyutsionnyj-period – free sheet music pdfs
http://sevenstring.ru/index.php/katalog-shkol – free Methods pdfs
http://www.lute.ru/guitar/persons_classics_russian_eng.htm – potted biographies of some composers
https://downthesoundhole.com The practice blog of non-Russian Russian-guitar player, with some nice videos.
More to follow…