Re: I'm touched by the weirdness of this request...
The nice thing about all the literary references in Pratchett is that he was far more well-read than I am - but there's sometimes a lovely sense of recognition as I come across something that I already know from a Discworld novel.
For example, I'm pretty sure I read Witches Abroad before I read Hemingway. There's a little 2 page parody in there that I only got when I read 'For Whom the Bell Tolls'. Which is also a great book by the way, but ever so slightly less cheerful than anything written by Sir Terry.