"life imprisonment and eight years" how exactly does this work?
It's an element of German law. I guess they can't enforce the eight years. :)
is saying things like "according to Langbein" and "Langbein notes" necessary, because if the reference is cited, it inherently comes from Langbein's book. Things like the attribution to Whittmann are necessary, as statements of fact.
Could you be specific as to which you think should be removed? Sometimes it is necessary to avoid putting a subjective statement in Wikipedia voice. The connection between Baretzki and Pestek should be attributed to Langbein to make it clear that it's not WP:OR.
"The following day" is this necessary? I'd assume that the beatings would occur on more than just the following day.
Specifically, Baretzki said that after viewing movies at night, they would go out the following morning to look for prisoners to beat up. I've tweaked this part for clarity.
Maybe add a translation of the german note into english (Ich bin doch nicht blind gewesen, als der Dr. Lucas auf der Rampe selektiert hat. … Fünftausend Mann, die hat er in einer halben Stunde ins Gas geschickt, und heute will er sich als Retter hinstellen)
This is the original German of the user-translated English quoted in text, "I was not blind when Dr. Lucas made selections on the ramp. ... Five thousand men he sent to the gas [chambers] in half an hour, and today he wants to stand as a savior" per MOS:FOREIGNQUOTE.
Done