diff --git a/Additional-Learning-Resources.md b/Additional-Learning-Resources.md
index b0aef1c..8da4973 100644
--- a/Additional-Learning-Resources.md
+++ b/Additional-Learning-Resources.md
@@ -16,8 +16,8 @@ Videos:
 + Mack Duan - Optimizing PDF.js, Mozilla, 2013, https://air.mozilla.org/intern-pdfjs/
 
 Slides:
-+ http://jviereck.github.com/slides/2012_07_berlinjs/index.html
-+ Yury Delendik - TTF 2012, [Evolving with Web Standards. The Story of PDF.JS.](https://people.mozilla.com/~ydelendik/pdfjs-ttf-2012.pdf)
++ https://jviereck.github.com/slides/2012_07_berlinjs/index.html
++ Yury Delendik - TTF 2012, [Evolving with Web Standards. The Story of PDF.JS.](https://web.archive.org/web/20161223213252if_/https://people.mozilla.com/~ydelendik/pdfjs-ttf-2012.pdf)
 + Brendan Dahl - HTML5DevConf 2013, http://brendandahl.github.io/speaking-events/2013-html5-dev-conf
 
 ## PDF-related resources