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.
Hilariously, all of Tolkien's shout-outs in the Lord of the Rings are to the tales in his own books, The Hobbit and the Silmarillion. He does not refer overtly to any other works outside of his mythologies of Middle-earth. That's what we call creating a self-sufficient universe. (If you want to find out more about Tolkien's literary influences in the creation of Middle-earth, check out our learning guide on The Hobbit.)