researching a Soviet army officer #russia


My paternal grandmother had a younger brother, Berko/Boris Yudin, born in 1898, who supposedly was a high level officer in the Soviet Army.  
Can someone suggest how I can research this relative?  I'd like to learn about his military service.  What sources would be relevant?  I don't read Russian.
Evan Fishman


Hello! If he participated in World War II as part of the Soviet Army, you can search here: 

Alexander Zaitsev, Saint Petersburg, Russia

Alex Den

hi. When did he serve in the RA? 
Alex Den