diff --git a/src/main/java/ca/joeltherrien/randomforest/covariates/numeric/NumericSplitRule.java b/src/main/java/ca/joeltherrien/randomforest/covariates/numeric/NumericSplitRule.java
index acc8e3b..c4e4150 100644
--- a/src/main/java/ca/joeltherrien/randomforest/covariates/numeric/NumericSplitRule.java
+++ b/src/main/java/ca/joeltherrien/randomforest/covariates/numeric/NumericSplitRule.java
@@ -1,3 +1,19 @@
+/*
+ * Copyright (c) 2019 Joel Therrien.
+ *     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 <https://www.gnu.org/licenses/>.
+ */
+
 package ca.joeltherrien.randomforest.covariates.numeric;
 
 import ca.joeltherrien.randomforest.covariates.Covariate;
diff --git a/src/test/java/ca/joeltherrien/randomforest/covariates/NumericCovariateTest.java b/src/test/java/ca/joeltherrien/randomforest/covariates/NumericCovariateTest.java
index 282d9d7..614aeeb 100644
--- a/src/test/java/ca/joeltherrien/randomforest/covariates/NumericCovariateTest.java
+++ b/src/test/java/ca/joeltherrien/randomforest/covariates/NumericCovariateTest.java
@@ -1,3 +1,19 @@
+/*
+ * Copyright (c) 2019 Joel Therrien.
+ *     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 <https://www.gnu.org/licenses/>.
+ */
+
 package ca.joeltherrien.randomforest.covariates;
 
 import ca.joeltherrien.randomforest.Row;
diff --git a/src/test/java/ca/joeltherrien/randomforest/nas/TestNAs.java b/src/test/java/ca/joeltherrien/randomforest/nas/TestNAs.java
index cb9a116..d60b13d 100644
--- a/src/test/java/ca/joeltherrien/randomforest/nas/TestNAs.java
+++ b/src/test/java/ca/joeltherrien/randomforest/nas/TestNAs.java
@@ -1,3 +1,19 @@
+/*
+ * Copyright (c) 2019 Joel Therrien.
+ *     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 <https://www.gnu.org/licenses/>.
+ */
+
 package ca.joeltherrien.randomforest.nas;
 
 import ca.joeltherrien.randomforest.Row;
diff --git a/src/test/java/ca/joeltherrien/randomforest/utils/RightContinuousStepFunctionIntegrationTest.java b/src/test/java/ca/joeltherrien/randomforest/utils/RightContinuousStepFunctionIntegrationTest.java
index 04de18b..f49155d 100644
--- a/src/test/java/ca/joeltherrien/randomforest/utils/RightContinuousStepFunctionIntegrationTest.java
+++ b/src/test/java/ca/joeltherrien/randomforest/utils/RightContinuousStepFunctionIntegrationTest.java
@@ -1,3 +1,19 @@
+/*
+ * Copyright (c) 2019 Joel Therrien.
+ *     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 <https://www.gnu.org/licenses/>.
+ */
+
 package ca.joeltherrien.randomforest.utils;
 
 import ca.joeltherrien.randomforest.TestUtils;