Fix broken link on transforming normals
diff --git a/doc/TutorialGeometry.dox b/doc/TutorialGeometry.dox
index 81aeec9..372a275 100644
--- a/doc/TutorialGeometry.dox
+++ b/doc/TutorialGeometry.dox
@@ -127,7 +127,7 @@
vec2 = t.linear() * vec1;\endcode</td></tr>
<tr><td>
Apply a \em general transformation \n to a \b normal \b vector
-(<a href="http://www.cgafaq.info/wiki/Transforming_normals">explanations</a>)</td><td>\code
+(<a href="http://femto.cs.uiuc.edu/faqs/cga-faq.html#S5.27">explanations</a>)</td><td>\code
VectorNf n1, n2;
MatrixNf normalMatrix = t.linear().inverse().transpose();
n2 = (normalMatrix * n1).normalized();\endcode</td></tr>