Hey fellow CGC citizens. Here's where and how to find Kent's custom Fresnel and Absorption Nodes:
It's in the Shader Forge Course. Go to #12 Marble. Download the source files for Marble. In your project, go to Append, click on the Marble download. Find "finish.blend" and click on that. Find "NodeTree" and click on that. There you will find both the Fresnel and the Absorption. Select them both and hit "Append from Library." There you go.
Thanks for sharing this, David! For the longest time these were buried in our educational source files. Not too long ago I posted them for easy download to the Blender Resources page under Utility Group Nodes.
Hey no problem. I did see you had posted that. However, there is something wrong with the "Utility Group Nodes" link. It seems to be stuck in a perpetual "loading" phase. Several others have reported this as well. So I figured me posting what I just did would be a fallback plan just in case. 
Sorry I just realized the "Utility Group Nodes" link only works if signed in. Duh! LOL