[James A Pratt III]

I am looking for info on a Russian WW I aviator and exile Georgiy Viktorovich Yankovsky or Jerzy-Witold 1888-1944. In 1941 his was in the Yugoslav armed forces. He later joined the Russian Corps in Yugoslavia. One account has him being killed while attemting to land a bomber damaged by Yugoslav partisans, alternate sources place his death at Sarajevo in 1943. Any one have any info on him?