I suggest you google up David Glantz' books
They are overwhelmingly expensive new, but a bit of canny shopping might get you there more affordably.
What is driving this is a combination of the purges of the 1930s crippling the Red Army leadership at (at least) division level upwards. Plus the losses of the summer/fall of 1941 crippling things even more.
There was a time in later '41 when the Red Army simply did not have any officers capable of division command in reserve, and pretty much none capable of corps command. So they abandoned the corps system, and new forming units were designated brigades - which was what they were, at best.
There is also the oft overlooked matter that the massive mechanised corps - truly a corps size unit in the western sense, with a combination of 3 large tank and mechanised divisons - had failed miserably in 1941. You can mount arguments that that was because they weren't fully equipped, their kit weas rubbish, they were under-strength, etc etc, but the Red Army terminated them and went to brigades, which as pointed out above, were later used as building blocks for a new "corps" mobile unit - which was basically a tank division.
All this learning on the job did lead eventually to the Guards Mechanized Corps, which is arguably the premier tank division (western size TOE) of the war.
"You may find that having is not so nearly pleasing a thing as wanting. It is not logical, but it is often true."
- Cdr Spock