fix cross ref

docs/modules/core/pages/gui/nifty_gui_java_layout.adoc

@@ -485,7 +485,7 @@ panel(new PanelBuilder("panel_mid") {{
 
 ----
 
-The font used is jME3's default font "`Interface/Fonts/Default.fnt`" which is included in the jMonkeyEngine.JAR. You can add your own fonts to your own `assets/Interface` directory. Set your font to the one you created during the start of the <<jme3/advanced/nifty_gui_xml_layout#implement-your-gui-layout#, Gui Implementation>> phase of your game.
+The font used is jME3's default font "`Interface/Fonts/Default.fnt`" which is included in the jMonkeyEngine.JAR. You can add your own fonts to your own `assets/Interface` directory. Set your font to the one you created during the start of the <<nifty_gui_xml_layout.adoc#implement-your-gui-layout, Gui Implementation>> phase of your game.
 
 
 === Add Controls

docs/modules/core/pages/gui/nifty_gui_overlay.adoc

@@ -27,7 +27,7 @@ On this page, we look at the overlay variant, which is more commonly used in gam
 
 [TIP]
 ====
-The jme3-niftygui library is included in jMonkeyEngine. If you installed jMonkeyEngine using one of the <<documentation#install,optional methods>>, it will be added to your projects Library folder as part of the installation. If you're using the jMonkeyEngine SDK, you add it to any project by btn:[RMB] selecting your projects `Library` folder, choosing `menu:Add Library[jme-niftygui]` followed by `Add Library`.
+The jme3-niftygui library is included in jMonkeyEngine. If you installed jMonkeyEngine using one of the <<ROOT:documentation.adoc#install,optional methods>>, it will be added to your projects Library folder as part of the installation. If you're using the jMonkeyEngine SDK, you add it to any project by btn:[RMB] selecting your projects `Library` folder, choosing `menu:Add Library[jme-niftygui]` followed by `Add Library`.
 ====