diff --git a/HEADER b/HEADER
new file mode 100644
index 0000000..54e04cc
--- /dev/null
+++ b/HEADER
@@ -0,0 +1,17 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/api/src/main/java/org/applecommander/applesingle/AppleSingle.java b/api/src/main/java/org/applecommander/applesingle/AppleSingle.java
index 8ada068..258859f 100644
--- a/api/src/main/java/org/applecommander/applesingle/AppleSingle.java
+++ b/api/src/main/java/org/applecommander/applesingle/AppleSingle.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle;
 
 import java.io.File;
diff --git a/api/src/main/java/org/applecommander/applesingle/AppleSingleReader.java b/api/src/main/java/org/applecommander/applesingle/AppleSingleReader.java
index c91aef8..d3795fd 100644
--- a/api/src/main/java/org/applecommander/applesingle/AppleSingleReader.java
+++ b/api/src/main/java/org/applecommander/applesingle/AppleSingleReader.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle;
 
 import java.nio.ByteBuffer;
diff --git a/api/src/main/java/org/applecommander/applesingle/Entry.java b/api/src/main/java/org/applecommander/applesingle/Entry.java
index c55dde8..a6a2f57 100644
--- a/api/src/main/java/org/applecommander/applesingle/Entry.java
+++ b/api/src/main/java/org/applecommander/applesingle/Entry.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle;
 
 import java.io.IOException;
diff --git a/api/src/main/java/org/applecommander/applesingle/EntryType.java b/api/src/main/java/org/applecommander/applesingle/EntryType.java
index c4f4e27..ff6899a 100644
--- a/api/src/main/java/org/applecommander/applesingle/EntryType.java
+++ b/api/src/main/java/org/applecommander/applesingle/EntryType.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle;
 
 public enum EntryType {
diff --git a/api/src/main/java/org/applecommander/applesingle/FileDatesInfo.java b/api/src/main/java/org/applecommander/applesingle/FileDatesInfo.java
index fb3a190..31ab2b2 100644
--- a/api/src/main/java/org/applecommander/applesingle/FileDatesInfo.java
+++ b/api/src/main/java/org/applecommander/applesingle/FileDatesInfo.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle;
 
 import java.nio.ByteBuffer;
diff --git a/api/src/main/java/org/applecommander/applesingle/ProdosFileInfo.java b/api/src/main/java/org/applecommander/applesingle/ProdosFileInfo.java
index 3f1ac83..9813f60 100644
--- a/api/src/main/java/org/applecommander/applesingle/ProdosFileInfo.java
+++ b/api/src/main/java/org/applecommander/applesingle/ProdosFileInfo.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle;
 
 import java.nio.ByteBuffer;
diff --git a/api/src/main/java/org/applecommander/applesingle/Utilities.java b/api/src/main/java/org/applecommander/applesingle/Utilities.java
index 0283bf0..4b4b907 100644
--- a/api/src/main/java/org/applecommander/applesingle/Utilities.java
+++ b/api/src/main/java/org/applecommander/applesingle/Utilities.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle;
 
 import java.io.ByteArrayOutputStream;
diff --git a/api/src/test/java/org/applecommander/applesingle/AppleSingleReaderTest.java b/api/src/test/java/org/applecommander/applesingle/AppleSingleReaderTest.java
index 9dd284a..0b7db47 100644
--- a/api/src/test/java/org/applecommander/applesingle/AppleSingleReaderTest.java
+++ b/api/src/test/java/org/applecommander/applesingle/AppleSingleReaderTest.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle;
 
 import org.junit.Test;
diff --git a/api/src/test/java/org/applecommander/applesingle/AppleSingleTest.java b/api/src/test/java/org/applecommander/applesingle/AppleSingleTest.java
index fc948f4..43f4a78 100644
--- a/api/src/test/java/org/applecommander/applesingle/AppleSingleTest.java
+++ b/api/src/test/java/org/applecommander/applesingle/AppleSingleTest.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle;
 
 import static org.junit.Assert.assertArrayEquals;
diff --git a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/AnalyzeCommand.java b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/AnalyzeCommand.java
index 7384735..652605a 100644
--- a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/AnalyzeCommand.java
+++ b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/AnalyzeCommand.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle.tools.asu;
 
 import java.io.IOException;
diff --git a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/CreateCommand.java b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/CreateCommand.java
index 379b27b..1e2ef71 100644
--- a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/CreateCommand.java
+++ b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/CreateCommand.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle.tools.asu;
 
 import java.io.IOException;
diff --git a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/EditCommand.java b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/EditCommand.java
index 488e312..1e07693 100644
--- a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/EditCommand.java
+++ b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/EditCommand.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle.tools.asu;
 
 import org.applecommander.applesingle.AppleSingle;
diff --git a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/ExtractCommand.java b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/ExtractCommand.java
index 0a916ed..b4d15a8 100644
--- a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/ExtractCommand.java
+++ b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/ExtractCommand.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle.tools.asu;
 
 import java.io.IOException;
diff --git a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/FilterCommand.java b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/FilterCommand.java
index ef317d9..30abb54 100644
--- a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/FilterCommand.java
+++ b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/FilterCommand.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle.tools.asu;
 
 import java.io.IOException;
diff --git a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/ForkType.java b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/ForkType.java
index fa3f039..0ed6e82 100644
--- a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/ForkType.java
+++ b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/ForkType.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle.tools.asu;
 
 /**
diff --git a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/HexDumper.java b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/HexDumper.java
index 7c3e751..1713fd6 100644
--- a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/HexDumper.java
+++ b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/HexDumper.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle.tools.asu;
 
 import java.io.PrintStream;
diff --git a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/InfoCommand.java b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/InfoCommand.java
index 60957cd..7f42e61 100644
--- a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/InfoCommand.java
+++ b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/InfoCommand.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle.tools.asu;
 
 import java.io.File;
diff --git a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/IntRange.java b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/IntRange.java
index eb018dd..7dd67d9 100644
--- a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/IntRange.java
+++ b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/IntRange.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle.tools.asu;
 
 import java.util.List;
diff --git a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/IntegerTypeConverter.java b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/IntegerTypeConverter.java
index f9d5e15..c30b363 100644
--- a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/IntegerTypeConverter.java
+++ b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/IntegerTypeConverter.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle.tools.asu;
 
 import picocli.CommandLine.ITypeConverter;
diff --git a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/Main.java b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/Main.java
index a5accf5..2d71119 100644
--- a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/Main.java
+++ b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/Main.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle.tools.asu;
 
 import java.util.Optional;
diff --git a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/NullOutputStream.java b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/NullOutputStream.java
index ca791c8..327bda2 100644
--- a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/NullOutputStream.java
+++ b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/NullOutputStream.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle.tools.asu;
 
 import java.io.IOException;
diff --git a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/ProdosFileTypeConverter.java b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/ProdosFileTypeConverter.java
index ef3cb44..6559943 100644
--- a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/ProdosFileTypeConverter.java
+++ b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/ProdosFileTypeConverter.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle.tools.asu;
 
 import java.util.HashMap;
diff --git a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/VersionProvider.java b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/VersionProvider.java
index dc43259..f069594 100644
--- a/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/VersionProvider.java
+++ b/tools/asu/src/main/java/org/applecommander/applesingle/tools/asu/VersionProvider.java
@@ -1,3 +1,20 @@
+/*
+ * AppleSingle - A Java library and command-line tool for AppleSingle support.
+ * Copyright (C) 2026  Robert Greene
+ *
+ * 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/>.
+ */
 package org.applecommander.applesingle.tools.asu;
 
 import org.applecommander.applesingle.AppleSingle;