The Two Towers
When authors refer to other great works, people, and events, it’s usually not accidental. Put on your super-sleuth hat and figure out why.
All of Tolkien's shout-outs in The Two Towers are to his own work. He mentions things that happen in his The Lord of the Rings prequel, The Hobbit, and in his collection of fictional elvish mythology, The Silmarillion. After all, The Two Towers is supposed to be taking place in Middle-earth, not our Earth. It would probably break the illusion if there were tons of references to other people's books and movies.