diff --git a/app/src/main/java/de/rochefort/childmonitor/ListenService.java b/app/src/main/java/de/rochefort/childmonitor/ListenService.java
index 835cdd5..548b707 100644
--- a/app/src/main/java/de/rochefort/childmonitor/ListenService.java
+++ b/app/src/main/java/de/rochefort/childmonitor/ListenService.java
@@ -1,3 +1,19 @@
+/*
+ * This file is part of Child Monitor.
+ *
+ * Child Monitor 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.
+ *
+ * Child Monitor 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 Child Monitor. If not, see <http://www.gnu.org/licenses/>.
+ */
 package de.rochefort.childmonitor;
 
 import static de.rochefort.childmonitor.AudioCodecDefines.CODEC;
diff --git a/app/src/main/java/de/rochefort/childmonitor/VolumeHistory.java b/app/src/main/java/de/rochefort/childmonitor/VolumeHistory.java
index 36d0035..e608c46 100644
--- a/app/src/main/java/de/rochefort/childmonitor/VolumeHistory.java
+++ b/app/src/main/java/de/rochefort/childmonitor/VolumeHistory.java
@@ -1,3 +1,19 @@
+/*
+ * This file is part of Child Monitor.
+ *
+ * Child Monitor 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.
+ *
+ * Child Monitor 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 Child Monitor. If not, see <http://www.gnu.org/licenses/>.
+ */
 package de.rochefort.childmonitor;
 
 import android.os.Handler;