Update link to example pbr asset

In Physically Based Rendering – Part one

src/docs/asciidoc/jme3/advanced/pbr_part1.adoc

@@ -74,7 +74,7 @@ These parameters are the basics of PBR. Of course, each of them can be stored in
 
 The nice thing is that Metalness, Roughness and AO are grey scaled textures, so basically they only use one channel of a texture. So you can pack those 3 maps in one texture.
 
-You can find an example asset that should work in a typical PBR implementation here. This page showcases pretty well what the textures should look like.
+You can find an example asset that should work in a typical PBR implementation link:http://artisaverb.info/PBT.html[here]. This page showcases pretty well what the textures should look like.
 
 That’s it for PBR from the artist point of view. Next week I’ll explain what’s under the hood for you fellow developers 😉