Updated README.md

README.md

@@ -1,18 +1,23 @@
 # blockchain-course
 
 [![Build LaTeX documents](https://github.com/spoto/blockchain-course/workflows/Build%20LaTeX%20documents/badge.svg)](https://github.com/spoto/blockchain-course/actions)
+[![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](http://www.apache.org/licenses/LICENSE-2.0.html)
 
 These are the slides of my course about blockchain technology at the
 University of Verona, Italy.
-You can download them in PDF format, from
-<a href="https://www.dropbox.com/sh/w0pz4betj0wqurq/AACPpBQNkJhGGiX7u2xDu9yUa?dl=0">this link</a>.
+You can download their latest version in PDF format from
+<a href="https://github.com/spoto/blockchain-course/releases">the releases page</a>.
 In alternative, you can regenerate the slides with the <code>build.sh</code> script
 (requires <code>pdflatex</code>).
 
-These slides cover the following arguments:
+These slides cover the following topics:
 
 * Introduction: introduction and history of the blockchain technology
 * Bitcoin: the bitcoin blockchain
 * Ethereum: the ethereum blockchain, including the Solidity language and smart contracts
 * Tendermint: the tendermint engine for creating PoS blokchains, including Cosmos
 * Hotmoka: the hotmoka nodes and the Takamaka language for programming smart contracts in Java
+
+<p align="center"><img width="100" src="https://mirrors.creativecommons.org/presskit/buttons/88x31/png/by.png" alt="This documentation is licensed under a Creative Commons Attribution 4.0 International License"></p><p align="center">This document is licensed under a Creative Commons Attribution 4.0 International License.</p>
+
+<p align="center">Copyright 2020-today by Fausto Spoto ([email protected])</p>