Russian sources of Yiddish/Klezmer Music?

[MaxwellSt <MaxwellSt...>]

First of all, thanks to all of you who posted your top choices for a klezmer 
library.  I am looking forward to expanding mine, thanks to your suggestions.

I would like to explore the Russian roots of Yiddish folk songs and Klezmer.  
Does anyone have a suggestion as to good examples or places to look for the 
connections?

I started out as a Russian major and found the shift to klezmer musician to 
be seamless.  The Russian sources interest me, such as how much Russian folk 
music was adopted/adapted by the Chassidim, which songs were transformed from 
Russian to Yiddish folk songs (if any), and so on.  I am more aware of the 
gypsy-klezmer connection than the Russian one, beyond the way that Jews have 
often 
favored certain Russian standards ("Dark Eyes") and not other, perhaps ones 
that reminded them more of the Cossacks, for example.

Does anyone have thoughts or insights?  Thanks, and shavua tov!
Lori