diff --git a/src/assembler.c b/src/assembler.c
index 8a2c3a6..54d3c1c 100644
--- a/src/assembler.c
+++ b/src/assembler.c
@@ -1,3 +1,21 @@
+/*
+ *	SPDX-License-Identifier: GPL-3.0-only
+ *
+ *	rk65c02
+ *	Copyright (C) 2017-2019  Radoslaw Kujawa
+ *
+ *	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, version 3 of the License.
+ * 
+ *	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/>.
+ */
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
diff --git a/src/bus.c b/src/bus.c
index 103963b..04ee727 100644
--- a/src/bus.c
+++ b/src/bus.c
@@ -1,3 +1,21 @@
+/*
+ *      SPDX-License-Identifier: GPL-3.0-only
+ *
+ *      rk65c02
+ *      Copyright (C) 2017-2019  Radoslaw Kujawa
+ *
+ *      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, version 3 of the License.
+ * 
+ *      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/>.
+ */
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
diff --git a/src/debug.c b/src/debug.c
index 3bdad04..086a03e 100644
--- a/src/debug.c
+++ b/src/debug.c
@@ -1,3 +1,21 @@
+/*
+ *      SPDX-License-Identifier: GPL-3.0-only
+ *
+ *      rk65c02
+ *      Copyright (C) 2017-2019  Radoslaw Kujawa
+ *
+ *      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, version 3 of the License.
+ * 
+ *      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/>.
+ */
 #include <stdio.h>
 #include <stdlib.h>
 
diff --git a/src/device_fb.c b/src/device_fb.c
index 785e625..fe6a2d3 100644
--- a/src/device_fb.c
+++ b/src/device_fb.c
@@ -1,3 +1,21 @@
+/*
+ *      SPDX-License-Identifier: GPL-3.0-only
+ *
+ *      rk65c02
+ *      Copyright (C) 2017-2019  Radoslaw Kujawa
+ *
+ *      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, version 3 of the License.
+ * 
+ *      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/>.
+ */
 #include <stdio.h>
 #include <stdlib.h>
 #include <assert.h>
diff --git a/src/device_ram.c b/src/device_ram.c
index bfb5ba6..c57d13d 100644
--- a/src/device_ram.c
+++ b/src/device_ram.c
@@ -1,3 +1,21 @@
+/*
+ *      SPDX-License-Identifier: GPL-3.0-only
+ *
+ *      rk65c02
+ *      Copyright (C) 2017-2019  Radoslaw Kujawa
+ *
+ *      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, version 3 of the License.
+ * 
+ *      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/>.
+ */
 #include <stdio.h>
 #include <stdlib.h>
 #include <assert.h>
diff --git a/src/device_serial.c b/src/device_serial.c
index 910ffcf..74f0753 100644
--- a/src/device_serial.c
+++ b/src/device_serial.c
@@ -1,3 +1,21 @@
+/*
+ *      SPDX-License-Identifier: GPL-3.0-only
+ *
+ *      rk65c02
+ *      Copyright (C) 2017-2019  Radoslaw Kujawa
+ *
+ *      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, version 3 of the License.
+ * 
+ *      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/>.
+ */
 #include <stdio.h>
 #include <stdlib.h>
 #include <assert.h>
diff --git a/src/emulation.c b/src/emulation.c
index d9cf2ff..e8a2218 100644
--- a/src/emulation.c
+++ b/src/emulation.c
@@ -1,3 +1,21 @@
+/*
+ *      SPDX-License-Identifier: GPL-3.0-only
+ *
+ *      rk65c02
+ *      Copyright (C) 2017-2019  Radoslaw Kujawa
+ *
+ *      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, version 3 of the License.
+ * 
+ *      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/>.
+ */
 #include <stdio.h>
 #include <assert.h>
 
diff --git a/src/instruction.c b/src/instruction.c
index 20d5e14..cadb7f8 100644
--- a/src/instruction.c
+++ b/src/instruction.c
@@ -1,3 +1,21 @@
+/*
+ *      SPDX-License-Identifier: GPL-3.0-only
+ *
+ *      rk65c02
+ *      Copyright (C) 2017-2019  Radoslaw Kujawa
+ *
+ *      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, version 3 of the License.
+ * 
+ *      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/>.
+ */
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
diff --git a/src/log.c b/src/log.c
index 6977497..0bf5179 100644
--- a/src/log.c
+++ b/src/log.c
@@ -1,3 +1,21 @@
+/*
+ *      SPDX-License-Identifier: GPL-3.0-only
+ *
+ *      rk65c02
+ *      Copyright (C) 2017-2019  Radoslaw Kujawa
+ *
+ *      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, version 3 of the License.
+ * 
+ *      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/>.
+ */
 #include <stdio.h>
 #include <stdarg.h>
 #include <time.h>
diff --git a/src/rk65c02.c b/src/rk65c02.c
index 681f151..b3df4a2 100644
--- a/src/rk65c02.c
+++ b/src/rk65c02.c
@@ -1,3 +1,21 @@
+/*
+ *      SPDX-License-Identifier: GPL-3.0-only
+ *
+ *      rk65c02
+ *      Copyright (C) 2017-2019  Radoslaw Kujawa
+ *
+ *      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, version 3 of the License.
+ * 
+ *      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/>.
+ */
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>