diff --git a/en/developer-documentation.md b/en/developer-documentation.md
index 590a8a75..83ec5498 100644
--- a/en/developer-documentation.md
+++ b/en/developer-documentation.md
@@ -80,7 +80,7 @@ title: "Developer Documentation - Bitcoin"
   <h2><img src="/img/ico_wiki.svg" class="titleicon" alt="Icon">Additional resources</h2>
   <p><a href="/bitcoin.pdf">Bitcoin: A Peer-to-Peer Electronic Cash System</a> - Satoshi Nakamoto</p>
   <p><a href="https://github.com/bitcoin/bips#readme">Bitcoin Improvement Proposals</a> - GitHub</p>
-  <p><a href="http://enetium.com/resources/Bitcoin.pdf">Bitcoin Protocol Specification (working paper)</a> - Krzysztof Okupski</p>
+  <p><a href="https://github.com/minium/Bitcoin-Spec">Bitcoin Developer Reference (working paper)</a> - Krzysztof Okupski</p>
   <p><a href="https://bitcoinj.github.io/#documentation">Bitcoinj Developer Documentation</a> - bitcoinj.org</p>
   <p><a href="https://en.bitcoin.it/wiki/Category:Technical">Technical Pages</a> - Wiki</p>
 </div></div>