diff --git a/resources.html b/resources.html
index 72b7805..c89dddf 100644
--- a/resources.html
+++ b/resources.html
@@ -121,7 +121,10 @@
 <h2>擴充版 Markdown</h2>
 
 <ul>
-<li><a href="https://help.github.com/articles/github-flavored-markdown">GitHub Flavored Markdown</a></li>
+<li><a href="https://help.github.com/articles/github-flavored-markdown">GitHub Flavored Markdown</a>
+<ul>
+<li><a href="https://github.github.com/gfm/">Spec</a></li>
+</ul></li>
 <li><a href="http://kramdown.rubyforge.org/quickref.html#headers">kramdown</a></li>
 <li><a href="http://fletcherpenney.net/multimarkdown/">MultiMarkdown</a></li>
 <li><a href="http://johnmacfarlane.net/pandoc/README.html#pandocs-markdown">Pandoc's markdown</a>
diff --git a/resources.md b/resources.md
index 5faff40..c068c55 100644
--- a/resources.md
+++ b/resources.md
@@ -68,6 +68,7 @@
 ## 擴充版 Markdown
 
 * [GitHub Flavored Markdown](https://help.github.com/articles/github-flavored-markdown)
+  * [Spec](https://github.github.com/gfm/)
 * [kramdown](http://kramdown.rubyforge.org/quickref.html#headers)
 * [MultiMarkdown](http://fletcherpenney.net/multimarkdown/)
 * [Pandoc's markdown](http://johnmacfarlane.net/pandoc/README.html#pandocs-markdown)
diff --git a/resources_content.html b/resources_content.html
index 6d9c099..51474f0 100644
--- a/resources_content.html
+++ b/resources_content.html
@@ -97,7 +97,10 @@
 <h2>擴充版 Markdown</h2>
 
 <ul>
-<li><a href="https://help.github.com/articles/github-flavored-markdown">GitHub Flavored Markdown</a></li>
+<li><a href="https://help.github.com/articles/github-flavored-markdown">GitHub Flavored Markdown</a>
+<ul>
+<li><a href="https://github.github.com/gfm/">Spec</a></li>
+</ul></li>
 <li><a href="http://kramdown.rubyforge.org/quickref.html#headers">kramdown</a></li>
 <li><a href="http://fletcherpenney.net/multimarkdown/">MultiMarkdown</a></li>
 <li><a href="http://johnmacfarlane.net/pandoc/README.html#pandocs-markdown">Pandoc's markdown</a>