claim: Estonia borders the line.
evidence: Moisei Iakovlevich Beregovsky -LRB- 18921961 -RRB- -LRB- the Hebrew first name is משה Moshe-for Moses , surname Beregovski or Beregovskii , in Yiddish בערעגאווסקי -RRB- , was a Soviet era -LRB- currently split between the Russian and Ukrainian -RRB- Jewish folklorist and ethnomusicologist .. Yiddish. Yiddish. Russian. Russian language. Ukrainian. Ukrainian language. Jewish. Jewish. folklorist. folklorist. ethnomusicologist. ethnomusicologist. He has been called the `` foremost ethnomusicologist of Eastern European Jewry '' .. ethnomusicologist. ethnomusicologist. His research gathered melodies and words of Yiddish folk songs , wordless melodies -LRB- nigunim -RRB- , as well as Eastern European Jewish dance melodies -LRB- klezmer music -RRB- .. Yiddish. Yiddish. Jewish. Jewish. nigunim. Nign. klezmer. klezmer