<li><a href="http://freico.in/docs/freimarkets.pdf">Freimarkets: a bitcoin extension to support user issued assets, p2p lending, options and more.</a></li>
<li><a href="http://blockstream.com/sidechains.pdf">Enabling Blockchain Innovations with Pegged Sidechains</a></li>
<li><a href="https://bitcoin.org/bitcoin.pdf">Bitcoin: A Peer-to-Peer Electronic Cash System</a></li>
<li><a href="http://freico.in/docs/freimarkets.pdf">Freimarkets: a bitcoin extension to support user issued assets, p2p lending, options and more.</a></li>
<li><a href="http://blockstream.com/sidechains.pdf">Enabling Blockchain Innovations with Pegged Sidechains</a></li>
<li><a href="https://bitcoin.org/bitcoin.pdf">Bitcoin: A Peer-to-Peer Electronic Cash System</a></li>
<li><a href="https://github.com/zw/PoLtree/">proving Bitcoin liabilities, in Clojure.</a> or <a href="https://github.com/olalonde/proof-of-liabilities">Proof of Liabilities, in JavaScript</a></li>
<li><a href="https://github.com/petertodd/timelock">Create a secret key that can be decrypted in a known amount of time using parallel-serial hash chains.</a></li>
<li><a href="https://github.com/Blockstream/contracthashtool">Pay to Contract Hash calculator</a></li>
<li><a href="https://github.com/zw/PoLtree/">proving Bitcoin liabilities, in Clojure.</a> or <a href="https://github.com/olalonde/proof-of-liabilities">Proof of Liabilities, in JavaScript</a></li>
<li><a href="https://github.com/petertodd/timelock">Create a secret key that can be decrypted in a known amount of time using parallel-serial hash chains.</a></li>
<li><a href="https://github.com/Blockstream/contracthashtool">Pay to Contract Hash calculator</a></li>