Harry Potter and the Deathly Hallows
Possible Historical Allusions
Since Potter-world is related to our world, but not actually in it, there aren't really any references to speak of. Basically, it refers back to earlier Harry Potter books, but not to anything outside that self-contained universe. Sure, there are hints of things that pertain to us – Grindelwald's attempted world domination in 1945 reminds us of Hitler's with its goals of (wizarding) racial purity, etc. Still, there are no direct shout-outs to anything in our so-called real-life world here.