diff --git a/documentation/NOTES.md b/documentation/NOTES.md
index 0d69478cf..714680d10 100644
--- a/documentation/NOTES.md
+++ b/documentation/NOTES.md
@@ -1,3 +1,8 @@
+# introduction
 * [Darstellung von XML-Daten](http://de.selfhtml.org/xml/darstellung/index.htm)
 * [How Not to Use XSLT](http://www.sims.berkeley.edu/academics/courses/is290-8/s04/lectures/5/dragons/allslides.html)
 * http://bobcat.webappcabaret.net/javachina/faq/xpath_01.htm#xpath_Q15 (b0rked?)
+
+# validation
+* [W3C online validation)[http://validator.w3.org/check)
+* local: ```make -j4```
\ No newline at end of file