sentences:  III./JG 52 was transferred to Bucharest in mid-October and temporarily renamed I./"Jagdgeschwader" 28 (I./JG 28) until 4 January 1941.During the Invasion of Yugoslavia of April 1941, III./JG 52 was kept back in reserve to guard the Ploiești oil installations.On 15 May, III./JG 52 was moved to Athens and together with other "Luftwaffe" units, flews its first combat missions in support of the Battle of Crete.