Merkle tree readings
Merkle trees were invented by Ralph Merkle in 1988 in an attempt to construct better digital signatures.
You can read Merkle's original paper or you can read this easier paper.
I think Merkle's paper is harder to read for a non cryptographer student because the paper describes Merkle trees in the context of signatures instead of a standalone tool, and is an old paper. The second reference is clearer and it also provides a simple application for Merkle trees.