If you doubt the translators, then look up the passage I provided and report. Note: it was you who included an unsourced, unreferenced, from memory, claim, while I took the trouble of skimming through hundreds of pages. Regarding the usage of a German source, read this: Wikipedia:Reliable_sources#Sources_in_languages_other_than_English. It says "English-language sources should be provided whenever possible" - if I could I'd use a Rissmann translation. The case of Kershaw is different, as this is not about referencing info in the article but about evaluating your claim, which turned to be ... well, read above.