Update README.md

README.md

@@ -10,6 +10,7 @@ Potsdam Institute for Climate Impact Research. All files are licenced under
 BSD 2-Clause License, see the LICENCE file for details. The 4C model is a 
 collaborative work, see the AUTHOR file for details.
 
+For information about the 4C model see "about".
 For a basic introduction and installation see the file .... 
 For manual on "how to start" see the directory manuals. 
 For background information documents see the directory description/additional.