Fix up all doxygen warnings.

doc/Overview.dox

@@ -6,14 +6,14 @@ This is the API documentation for Eigen3. You can <a href="eigen-doc.tgz">downlo
 
 You're already an Eigen2 user? Here is a \link Eigen2ToEigen3 Eigen2 to Eigen3 guide \endlink to help porting your application.
 
-For a first contact with Eigen, the best place is to have a look at the \link GettingStarted getting started \endlink page that show you how to write and compile your first program with Eigen.
+For a first contact with Eigen, the best place is to have a look at the \subpage GettingStarted page that show you how to write and compile your first program with Eigen.
 
 Then, the \b quick \b reference \b pages give you a quite complete description of the API in a very condensed format that is specially useful to recall the syntax of a particular feature, or to have a quick look at the API. They currently cover the two following feature sets, and more will come in the future:
   - \link QuickRefPage [QuickRef] Dense matrix and array manipulations \endlink
   - \link SparseQuickRefPage [QuickRef] Sparse linear algebra \endlink
 
 You're a MatLab user? There is also a <a href="AsciiQuickReference.txt">short ASCII reference</a> with Matlab translations.
-  
+
 The \b main \b documentation is organized into \em chapters covering different domains of features.
 They are themselves composed of \em user \em manual pages describing the different features in a comprehensive way, and \em reference pages that gives you access to the API documentation through the related Eigen's \em modules and \em classes.
 
@@ -21,6 +21,10 @@ Under the \subpage UserManual_CustomizingEigen section, you will find discussion
 
 Under the \subpage UserManual_Generalities section, you will find documentation on more general topics such as preprocessor directives, controlling assertions, multi-threading, MKL support, some Eigen's internal insights, and much more...
 
+For details regarding Eigen's inner-workings, see the \subpage UserManual_UnderstandingEigen section.
+
+Some random topics can be found under the \subpage UnclassifiedPages section.
+
 Finally, do not miss the search engine, useful to quickly get to the documentation of a given class or function.
 
 Want more? Checkout the <a href="unsupported/index.html">\em unsupported \em modules </a> documentation.