Update readme

README.md

@@ -9,6 +9,9 @@ Double-click `anaconda-prompt.bat`
 
 #### 2. Generate ZSA and ZRFC recession tables.
 
+The package required to calculate setbacks based on Nielsen et al. (1992) can be found here:  
+http://git.wrl.unsw.edu.au:3000/coastal/nielsen
+
 ```shell
   > cd lidar  
   > python generate_recession_tables.py