diff --git a/README.md b/README.md
index cef20a5bc75eb48a494148946e1c6f438e2b86c6..4ccf9edc9e112981e3cd778330d6c938b046bc84 100644
--- a/README.md
+++ b/README.md
@@ -10,4 +10,17 @@ The current implementation offers a set of elementary tests to check that the or
 
 # License
 
-This project is distributed under the terms of the *GNU General Public License V3.0 or later* (GPL-3.0-or-later). Check the contents of the *COPYING* file for further details.
\ No newline at end of file
+   Copyright 2004 INAF - Osservatorio Astronomico di Cagliari
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+   
\ No newline at end of file
diff --git a/build/README.md b/build/README.md
index bd4fe07fd2a7db8b7b645a23a001180531071154..26ca5880008cb1d4adcfddfb3a5e6c144f5c4a55 100644
--- a/build/README.md
+++ b/build/README.md
@@ -1,5 +1,3 @@
-Distributed under the terms of *GNU GPL-3.0-or-later*
-
 # Folder instructions
 
 This directory collects all the output of make builds.
@@ -97,3 +95,20 @@ This program checks for the consistency of transition matrix data files. It is e
 > ./test_TTMS PATH_TO_c_TTMS PATH_TO_c_TTMS.hd5
 
 where the arguments must be valid paths to binary transition matrix files saved in the legaci or the _HDF5_ format. Similarly to the previous case, the program writes a short log and returns a result value of 0, for success, or a positive number in case of inconsistency detection.
+
+# License
+
+   Copyright 2004 INAF - Osservatorio Astronomico di Cagliari
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+   
\ No newline at end of file
diff --git a/containers/docker/README.md b/containers/docker/README.md
index 555a487d89a97d85acd42a412e535e3ba6e383ff..46e5d752af612bf4850f0e5d65cadafb01c27140 100644
--- a/containers/docker/README.md
+++ b/containers/docker/README.md
@@ -1,5 +1,3 @@
-Distributed under the terms of *GNU GPL-3.0-or-later*
-
 # Docker support for the NP-TMcode project
 
 This Dockerfile allows to create mainly:
@@ -11,4 +9,21 @@ In order for the docker build to correctly set the context, so that it can acces
 
    > docker build -f Dockerfile ../.. --target \<image name\>
 
-where `<image name>` is either `np-tmcode` or `np-tmcode-run`. One may also add the docker build option `-t tagname` to specify the `tagname` the built image should have in his/her registry.
\ No newline at end of file
+where `<image name>` is either `np-tmcode` or `np-tmcode-run`. One may also add the docker build option `-t tagname` to specify the `tagname` the built image should have in his/her registry.
+
+# License
+
+   Copyright 2004 INAF - Osservatorio Astronomico di Cagliari
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+   
\ No newline at end of file
diff --git a/containers/singularity/README.md b/containers/singularity/README.md
index 20e9767c4df0e96126e41ef74e1b3b4b941dda42..0f400330c55328f9621059db4cda984e1ba59cae 100644
--- a/containers/singularity/README.md
+++ b/containers/singularity/README.md
@@ -1,5 +1,3 @@
-Distributed under the terms of *GNU GPL-3.0-or-later*
-
 # Singularity support for the NP-TMcode project
 
 This `np-tmcode-run.def` file allows to create a np-tmcode-run image, that contains only the pre-built executables, python test scripts, compiled documentation, and the minimal runtime to run them
@@ -18,4 +16,21 @@ or directly as
 
    > \<full path to image name\> \<np-tmcode command\>
 
-where `<full path to image name>` is the name of the sif image, including full or relative path to it, and `<np-tmcode command>` is one of the executables built in np-tmcode project, or the `pycompare.py` script used to compare results between the Fortran and C++ versions of the code. These executables, as well as the minimum runtime for them to execute correctly, are embedded in the image, and "see" the current directory the image is run in (which technically is automatically bind-mounted by singularity in the running image instance).
\ No newline at end of file
+where `<full path to image name>` is the name of the sif image, including full or relative path to it, and `<np-tmcode command>` is one of the executables built in np-tmcode project, or the `pycompare.py` script used to compare results between the Fortran and C++ versions of the code. These executables, as well as the minimum runtime for them to execute correctly, are embedded in the image, and "see" the current directory the image is run in (which technically is automatically bind-mounted by singularity in the running image instance).
+
+# License
+
+   Copyright 2004 INAF - Osservatorio Astronomico di Cagliari
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+   
\ No newline at end of file
diff --git a/doc/src/README.md b/doc/src/README.md
index 40ca9e988adb0865d58cb2011fb40b4bda0e3244..55f445eb0cbcd88e5d5ace491628e0394c034be5 100644
--- a/doc/src/README.md
+++ b/doc/src/README.md
@@ -1,5 +1,3 @@
-Distributed under the terms of *GNU GPL-3.0-or-later*
-
 # Folder instructions
 
 This directory contains the material to build the project documentation with *doxygen*.
@@ -14,4 +12,21 @@ Alternatively, you can use `make` from the project `src` folder (named `np_tmcod
 
 > make docs
 
-*doxygen* will automatically build the HTML structure to cover all the documented source code and it will additionally provide the fundamental structure to prepare a LaTeX formatted version of the documents. These two outputs will be placed, respectively, under the folders `np_tmcode/doc/build/html` and `np_tmcode/doc/build/latex`.
\ No newline at end of file
+*doxygen* will automatically build the HTML structure to cover all the documented source code and it will additionally provide the fundamental structure to prepare a LaTeX formatted version of the documents. These two outputs will be placed, respectively, under the folders `np_tmcode/doc/build/html` and `np_tmcode/doc/build/latex`.
+
+# License
+
+   Copyright 2004 INAF - Osservatorio Astronomico di Cagliari
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+   
\ No newline at end of file
diff --git a/src/README.md b/src/README.md
index 803470ee896cabebd92f61f297f971030136e1d4..a665a1d843acfe397daa639d56892aa34f173646 100644
--- a/src/README.md
+++ b/src/README.md
@@ -1,5 +1,3 @@
-Distributed under the terms of *GNU GPL-3.0-or-later*
-
 # Folder instructions
 
 This directory collects the source code of the original programs and the development folders.
@@ -37,3 +35,20 @@ In all cases, build commands executed through `make` will output the object file
    > ./np_cluster
 
 7. Check the consistency between the text files named `OCLU` and `c_OCLU`
+
+# License
+
+   Copyright 2004 INAF - Osservatorio Astronomico di Cagliari
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+   
\ No newline at end of file
diff --git a/src/scripts/README.md b/src/scripts/README.md
index 59a757141c8c6627065b4b809e774a0bc9f079fd..2bda93b8fd8a238cfc1760f977b099db5207c6f4 100644
--- a/src/scripts/README.md
+++ b/src/scripts/README.md
@@ -1,5 +1,3 @@
-Distributed under the terms of *GNU GPL-3.0-or-later*
-
 # Folder instructions
 
 This directory contains scripts and tools to evaluate the code functionality.
@@ -27,4 +25,21 @@ or just:
 
    > $PATH_TO_SCRIPT/pycompare.py
 
-will print a help screen, giving a brief explanation of all the possible options.
\ No newline at end of file
+will print a help screen, giving a brief explanation of all the possible options.
+
+# License
+
+   Copyright 2004 INAF - Osservatorio Astronomico di Cagliari
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+   
\ No newline at end of file
diff --git a/test_data/README.md b/test_data/README.md
index 4db4e5af7e9ab05240bbd9a95fb0d6f0efb0a80c..7c60da1433a04d4f4174e1a7f64431f42a23acdd 100644
--- a/test_data/README.md
+++ b/test_data/README.md
@@ -1,5 +1,3 @@
-Distributed under the terms of *GNU GPL-3.0-or-later*
-
 # Folder instructions
 
 This directory collects the input files to test the code.
@@ -61,3 +59,20 @@ were the different lines have the following roles:
 3. definition of the azimuth angle arrays for the incident and scattered radiation fields
 4. a flag to set whether the intermediate data should be written to output files
 5. an end-of-file code (generally 0)
+
+# License
+
+   Copyright 2004 INAF - Osservatorio Astronomico di Cagliari
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+   
\ No newline at end of file