"The Russian Collection", volumes 1 trough 6, from Editions Orphee. They were cheap on e - b a y. Transcribed from the 7 string guitar to 6 string by Matanya Orphee. Tons of really good 19th century music. There are 9 volumes, so I will have to pay retail for the rest. If you're into romantic music, this is really worth looking into. A real breath of fresh air. Very well printed, good layout, with brief bios, notes,etc., lovingly researched. They are reasonably priced, I just happened to get a great deal for the lot.
Here's a link to a series on Russian guitar music: