Add a file detailing the additional restrictions.

license.additional

+    Under Section 7 of GPL version 3 we require you to fulfill the following additional terms:
+    
+    - It is our hope that this program makes a contribution to the scientific community. Being
+      part of that community we feel that it is reasonable to require you to give an attribution
+      back to the original authors if you have benefitted from this program.
+      Guidelines for a proper citation can be found on the project's homepage
+      http://alf.physik.uni-wuerzburg.de .
+      
+    - We require the preservation of the above copyright notice and this license in all original files.
+    
+    - We prohibit the misrepresentation of the origin of the original source files. To obtain 
+      the original source files please visit the homepage http://alf.physik.uni-wuerzburg.de .
+
+    - If you make substantial changes to the program we require you to either consider contributing
+      to the ALF project or to mark your material in a reasonable way as different from the original version.