Roubaud, Azersky and the unknown author - It is difficult to estimate?

[Konstantin]

We Roubaud, Franz Alekseevich, the main theme of creativity - the Caucasus.
The theme of water but have never met. Most likely it is not.

Azersky, I looked in the bibliographical dictionary of "Artists of the USSR" 11-20 century an artist is not there.

And if it is unknown artists, but at that time, the price for them
1000 - 1500 $ and will be difficult to sell. Advise the gallery can not.
Can members of the forum who will advise.
You can try to hang in private advertisements on this site.