Bulgarian air force Cpl. Stoyko V. Stoykov salutes with U.S. Airmen and classmates August 15, 2013, during a reveille ceremony at McGhee Tyson Air National Guard Base, Tenn. Stoykov graduated from Airman Leadership School along with Bulgarian Sergeant Yordanka S. Petrova-Angelova, who graduated from the NCO Academy, as a result of international relations built through the Tennessee National Guard State Partnership Program.