Sources:
'Barbarossa' - A. Clark
'Stalingrad' - A. Beevor
'World at War' - BBC Tv series
History teacher
Sorry but LOL.
Barbarossa was based on the testimony of captured nazis trying to justify to their US captors that they had to do what they did cos they were fighting subhumans who send their own men into battle unarmed. Come the cold war no-one was particularly inclined in the west to check the veracity of this stuff.
Beevor's research includes such gems as saying that one division commander practiced decimation (in the strict Roman sense) without quoting any sources at all.
World at War used Barbarossa as source material IIRC.
A moment's thought would make you realise the absolute pointlessness of forcing men to charge into battle without guns... and would also make you realise why it was in the captured nazis' interests to portray the red army as some kind of orc horde. The Soviet regime was evil in many ways but it was not stupid nor particularly suicidal.
Check a proper western historian of soviet military history's take on the events... someone like Col. David Glantz.. and you will see examples of brutality and incompetence alongside heroism and skill.. but nothing like the travesty "Enemy at the gates".