What is an example of a movie allusion?

Example: In the movie "The Shawshank Redemption," when Red tells Andy, "Remember, hope is a good thing, maybe the best of things, and no good thing ever dies," this is a reference to the poem "Invictus" by William Ernest Henley. The poem includes the line "In the fell clutch of circumstance, I have not winced nor cried aloud./Under the bludgeonings of chance, My head is bloody, but unbowed."