diff --git a/NIH_notice b/NIH_notice
new file mode 100644
index 0000000..22ee250
--- /dev/null
+++ b/NIH_notice
@@ -0,0 +1,26 @@
+==============================================================
+
+                     PUBLIC DOMAIN NOTICE
+                National Institutes of Health
+
+This software is a "United States Government Work" under the 
+terms of the United States Copyright Act.  It was written as 
+part of the authors' official duties as United States 
+Government employees and thus cannot be copyrighted.  This 
+software is freely available to the public for use. The 
+National Institutes of Health and the U.S. Government have not
+placed any restriction on its use or reproduction.
+
+Although all reasonable efforts have been taken to ensure 
+the accuracy and reliability of the software and data, the 
+NIH and the U.S. Government do not and cannot warrant the 
+performance or results that may be obtained by using this 
+software or data. The NIH and the U.S. Government disclaim 
+all warranties, express or implied, including warranties of 
+performance, merchantability or fitness for any particular 
+purpose.
+
+Please cite the authors in any work or product based on this 
+material.
+
+==============================================================
diff --git a/go_builder/go_builder.py b/go_builder/go_builder.py
index 75bb88a..feeb82b 100755
--- a/go_builder/go_builder.py
+++ b/go_builder/go_builder.py
@@ -1,3 +1,32 @@
+'''
+==============================================================
+
+                     PUBLIC DOMAIN NOTICE
+                National Institutes of Health
+
+This software is a "United States Government Work" under the
+terms of the United States Copyright Act.  It was written as
+part of the authors' official duties as United States
+Government employees and thus cannot be copyrighted.  This
+software is freely available to the public for use. The
+National Institutes of Health and the U.S. Government have not
+placed any restriction on its use or reproduction.
+
+Although all reasonable efforts have been taken to ensure
+the accuracy and reliability of the software and data, the
+NIH and the U.S. Government do not and cannot warrant the
+performance or results that may be obtained by using this
+software or data. The NIH and the U.S. Government disclaim
+all warranties, express or implied, including warranties of
+performance, merchantability or fitness for any particular
+purpose.
+
+Please cite the authors in any work or product based on this
+material.
+
+==============================================================
+'''
+
 # Entry point to construct GO models
 
 import copy,getopt,os,sys
diff --git a/go_builder/go_lib.py b/go_builder/go_lib.py
index a70c0d1..f564f78 100755
--- a/go_builder/go_lib.py
+++ b/go_builder/go_lib.py
@@ -1,3 +1,31 @@
+'''
+==============================================================
+
+                     PUBLIC DOMAIN NOTICE
+                National Institutes of Health
+
+This software is a "United States Government Work" under the
+terms of the United States Copyright Act.  It was written as
+part of the authors' official duties as United States
+Government employees and thus cannot be copyrighted.  This
+software is freely available to the public for use. The
+National Institutes of Health and the U.S. Government have not
+placed any restriction on its use or reproduction.
+
+Although all reasonable efforts have been taken to ensure
+the accuracy and reliability of the software and data, the
+NIH and the U.S. Government do not and cannot warrant the
+performance or results that may be obtained by using this
+software or data. The NIH and the U.S. Government disclaim
+all warranties, express or implied, including warranties of
+performance, merchantability or fitness for any particular
+purpose.
+
+Please cite the authors in any work or product based on this
+material.
+
+==============================================================
+'''
 
 # Library of useful functions for constructing GO models
 
diff --git a/tadoss.py b/tadoss.py
index 3bb6495..0a251b2 100644
--- a/tadoss.py
+++ b/tadoss.py
@@ -1,3 +1,32 @@
+'''
+==============================================================
+
+                     PUBLIC DOMAIN NOTICE
+                National Institutes of Health
+
+This software is a "United States Government Work" under the
+terms of the United States Copyright Act.  It was written as
+part of the authors' official duties as United States
+Government employees and thus cannot be copyrighted.  This
+software is freely available to the public for use. The
+National Institutes of Health and the U.S. Government have not
+placed any restriction on its use or reproduction.
+
+Although all reasonable efforts have been taken to ensure
+the accuracy and reliability of the software and data, the
+NIH and the U.S. Government do not and cannot warrant the
+performance or results that may be obtained by using this
+software or data. The NIH and the U.S. Government disclaim
+all warranties, express or implied, including warranties of
+performance, merchantability or fitness for any particular
+purpose.
+
+Please cite the authors in any work or product based on this
+material.
+
+==============================================================
+'''
+
 import numpy as np
 import argparse as ap
 import warnings