diff --git a/.copyright.tmpl b/.copyright.tmpl
new file mode 100644
index 0000000..1f415b7
--- /dev/null
+++ b/.copyright.tmpl
@@ -0,0 +1,17 @@
+Copyright (c) ${years} Maxim Slipenko, Euegene Lazurenko.
+
+This file is part of Statapp
+(see https://github.com/shizand/statapp).
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index fd16ba2..a810059 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -8,3 +8,9 @@ repos:
     -   id: end-of-file-fixer
     -   id: check-yaml
     -   id: check-added-large-files
+-   repo: https://github.com/johann-petrak/licenseheaders.git
+    rev: 'master'
+    hooks:
+        - id: licenseheaders
+          args: ["-t", ".copyright.tmpl", "-cy", "-f", "-d statapp"]
+          pass_filenames: false
diff --git a/statapp/__main__.py b/statapp/__main__.py
index 7f6ccba..c31cb10 100644
--- a/statapp/__main__.py
+++ b/statapp/__main__.py
@@ -1,3 +1,21 @@
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
 import sys
 
 from PySide2 import QtCore
diff --git a/statapp/about_window.py b/statapp/about_window.py
index c4253c3..72c213a 100644
--- a/statapp/about_window.py
+++ b/statapp/about_window.py
@@ -1,3 +1,21 @@
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
 import sys
 from PySide2.QtGui import QMovie
 from PySide2.QtWidgets import QMainWindow
diff --git a/statapp/calculations.py b/statapp/calculations.py
index 208eae9..6ab70ec 100644
--- a/statapp/calculations.py
+++ b/statapp/calculations.py
@@ -1,3 +1,21 @@
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
 import numpy as np
 
 DIRECT_LINK = 0
@@ -24,4 +42,4 @@ def generate_x_values(mean, std, typeConnection, y):
 def variance_analysis(data):
     return np.array([
         [np.mean(col), np.std(col), np.min(col), np.max(col)] for col in data.T
-    ])
\ No newline at end of file
+    ])
diff --git a/statapp/generate_factor_window.py b/statapp/generate_factor_window.py
index 08dd441..a84a836 100644
--- a/statapp/generate_factor_window.py
+++ b/statapp/generate_factor_window.py
@@ -1,3 +1,21 @@
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
 from PySide2.QtCore import Slot
 from PySide2.QtWidgets import QDialog
 
diff --git a/statapp/generate_window.py b/statapp/generate_window.py
index 7785bcd..2170e28 100644
--- a/statapp/generate_window.py
+++ b/statapp/generate_window.py
@@ -1,3 +1,21 @@
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
 from PySide2.QtCore import Slot
 from PySide2.QtWidgets import QDialog
 
diff --git a/statapp/main_window.py b/statapp/main_window.py
index e6e02f0..a146f90 100644
--- a/statapp/main_window.py
+++ b/statapp/main_window.py
@@ -1,3 +1,21 @@
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
 import numpy as np
 from PySide2.QtCore import Slot, QLocale, QSize
 from PySide2.QtGui import QIcon
diff --git a/statapp/models/combobox_model.py b/statapp/models/combobox_model.py
index cc33814..e599180 100644
--- a/statapp/models/combobox_model.py
+++ b/statapp/models/combobox_model.py
@@ -1,3 +1,21 @@
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
 from PySide2.QtCore import QAbstractListModel, Qt
 
 
diff --git a/statapp/models/editable_table_model.py b/statapp/models/editable_table_model.py
index e2328e6..907e565 100644
--- a/statapp/models/editable_table_model.py
+++ b/statapp/models/editable_table_model.py
@@ -1,3 +1,21 @@
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
 import numpy as np
 from PySide2.QtCore import Qt
 
diff --git a/statapp/models/fileslc_model.py b/statapp/models/fileslc_model.py
index 104a292..e998e6a 100644
--- a/statapp/models/fileslc_model.py
+++ b/statapp/models/fileslc_model.py
@@ -1,3 +1,21 @@
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
 import numpy as np
 from PySide2.QtWidgets import QFileDialog, QMessageBox
 
diff --git a/statapp/models/input_values_model.py b/statapp/models/input_values_model.py
index 6f5629c..1151ab2 100644
--- a/statapp/models/input_values_model.py
+++ b/statapp/models/input_values_model.py
@@ -1,3 +1,21 @@
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
 import numpy as np
 from PySide2.QtCore import Qt, QModelIndex
 
diff --git a/statapp/models/ro_table_model.py b/statapp/models/ro_table_model.py
index aad69aa..6794a38 100644
--- a/statapp/models/ro_table_model.py
+++ b/statapp/models/ro_table_model.py
@@ -1,3 +1,21 @@
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
 import PySide2
 import numpy as np
 from PySide2 import QtCore
diff --git a/statapp/models/utils.py b/statapp/models/utils.py
index 6f8b3ba..fc18abf 100644
--- a/statapp/models/utils.py
+++ b/statapp/models/utils.py
@@ -1,2 +1,20 @@
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
 def yx_header(count):
     return ['Y'] + [f'X{i}' for i in range(1, count)]
diff --git a/statapp/models/variance_analysis_model.py b/statapp/models/variance_analysis_model.py
index fc37522..f760901 100644
--- a/statapp/models/variance_analysis_model.py
+++ b/statapp/models/variance_analysis_model.py
@@ -1,3 +1,21 @@
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
 from PySide2.QtCore import QModelIndex
 
 from statapp.models.ro_table_model import ROTableModel
diff --git a/statapp/ui/ui_about_window.py b/statapp/ui/ui_about_window.py
index 2bafd32..8c9610a 100644
--- a/statapp/ui/ui_about_window.py
+++ b/statapp/ui/ui_about_window.py
@@ -1,4 +1,23 @@
 # -*- coding: utf-8 -*-
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
+
 
 ################################################################################
 ## Form generated from reading UI file 'about_window.ui'
diff --git a/statapp/ui/ui_generate_factor_window.py b/statapp/ui/ui_generate_factor_window.py
index 01c3cb1..78507c7 100644
--- a/statapp/ui/ui_generate_factor_window.py
+++ b/statapp/ui/ui_generate_factor_window.py
@@ -1,4 +1,23 @@
 # -*- coding: utf-8 -*-
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
+
 
 ################################################################################
 ## Form generated from reading UI file 'generate_factor_window.ui'
diff --git a/statapp/ui/ui_generate_window.py b/statapp/ui/ui_generate_window.py
index e3c8628..cd64a33 100644
--- a/statapp/ui/ui_generate_window.py
+++ b/statapp/ui/ui_generate_window.py
@@ -1,4 +1,23 @@
 # -*- coding: utf-8 -*-
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
+
 
 ################################################################################
 ## Form generated from reading UI file 'generate_window.ui'
diff --git a/statapp/ui/ui_main_window.py b/statapp/ui/ui_main_window.py
index bfd7bfd..cef9cf1 100644
--- a/statapp/ui/ui_main_window.py
+++ b/statapp/ui/ui_main_window.py
@@ -1,4 +1,23 @@
 # -*- coding: utf-8 -*-
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
+
 
 ################################################################################
 ## Form generated from reading UI file 'main_window.ui'
diff --git a/statapp/ui/ui_variance_analysis_window.py b/statapp/ui/ui_variance_analysis_window.py
index 7cea5c2..3dd17e8 100644
--- a/statapp/ui/ui_variance_analysis_window.py
+++ b/statapp/ui/ui_variance_analysis_window.py
@@ -1,4 +1,23 @@
 # -*- coding: utf-8 -*-
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
+
 
 ################################################################################
 ## Form generated from reading UI file 'variance_analysis_window.ui'
diff --git a/statapp/utils.py b/statapp/utils.py
index 9dbc210..568c51c 100644
--- a/statapp/utils.py
+++ b/statapp/utils.py
@@ -1,3 +1,21 @@
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
 import os
 import sys
 
diff --git a/statapp/variance_analysis.py b/statapp/variance_analysis.py
index df8476a..e6252b4 100644
--- a/statapp/variance_analysis.py
+++ b/statapp/variance_analysis.py
@@ -1,3 +1,21 @@
+#
+# Copyright (c) 2023 Maxim Slipenko, Euegene Lazurenko.
+#
+# This file is part of Statapp
+# (see https://github.com/shizand/statapp).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.#
 from PySide2.QtWidgets import QDialog, QHeaderView
 
 from statapp.calculations import variance_analysis