Didn't I put a reference to Chuck Hamill's From Crossbows to Cryptography into my Assassination Politics essay?

I just did a search of my AP essay.  I didn't find a reference to Chuck Hamill's essay, "From Crossbows to Cryptography" in it.   https://nakamotoinstitute.org/static/docs/from-crossbows-to-cryptography.pdf... is going on?   I cannot imagine NOT having cited Hamill's essay.  It, perhaps more than any other single thing, inspired me to write my AP essay. Please help me solve this.                   Jim Bell