The source for these claims came from
www.airforce.ru
04 Aug 1942
LaGG-3 5 GIAP Mayor Grigoriy Denisovich Onufrienko
Hptm. Hartmann Grasser Stab/JG 51 LaGG-3 (69) 12:05 PlQu. 47524 at 2500 m.
04 Aug 1942
Lt. Guenther Ruebell Stab II/JG 51 LaGG-3 (37) 12:25 PlQu. 47552 at 2000 m.
According to what I found there it stated that the LaGG-3 5 GIAP Lt. Ibragim Shagiakhmedovich Bikmukhametov rammed Bf 109 F-2 (# 9564). He then returned to his airfield and landed his damaged fighter. It indicated that this was Rueben's Bf 109.
In Prien's JFV 9/II it stated this 5./JG 51 Bf 109 went down in an air battle at Rzhev with the pilot unnamed at 100%. I ran across another post which stated that Onufrienko claimed his 15th victory on the 04 Aug 1942 but what kind of aircraft I don't know.