diff --git a/README.adoc b/README.adoc
index d5f91fc..d6a5fcd 100644
--- a/README.adoc
+++ b/README.adoc
@@ -8109,6 +8109,13 @@ The Linux kernel exposes physical addresses to userland through:
 
 In this section we will play with them.
 
+The following files contain examples to access that data and test it out:
+
+* link:lkmc/pagemap.h[]
+* link:rootfs_overlay/lkmc/virt_to_phys.sh[]
+* link:userland/linux/virt_to_phys_user.c[]
+* link:userland/posix/virt_to_phys_test.c[]
+
 First get a virtual address to play with:
 
 ....
@@ -8142,8 +8149,6 @@ Sample output physical address:
 0x7c7b800
 ....
 
-Source: link:userland/linux/virt_to_phys_user.c[]
-
 Now we can verify that `linux/virt_to_phys_user.out` gave the correct physical address in the following ways:
 
 * <<qemu-xp>>
diff --git a/lkmc/pagemap.h b/lkmc/pagemap.h
index ddba470..36a4bb7 100644
--- a/lkmc/pagemap.h
+++ b/lkmc/pagemap.h
@@ -1,3 +1,9 @@
+/* https://cirosantilli.com/linux-kernel-module-cheat#userland-physical-address-experiments
+ * https://cirosantilli.com/linux-kernel-module-cheat#pagemap-dump-out
+ *
+ * This file is dual licensed as both 3-Clause BSD and GPLv3.
+ */
+
 #ifndef LKMC_PAGEMAP_H
 #define LKMC_PAGEMAP_H
 
diff --git a/userland/linux/pagemap_dump.c b/userland/linux/pagemap_dump.c
index 2579fb0..e22b2db 100644
--- a/userland/linux/pagemap_dump.c
+++ b/userland/linux/pagemap_dump.c
@@ -1,4 +1,7 @@
-/* https://cirosantilli.com/linux-kernel-module-cheat#pagemap-dump-out */
+/* https://cirosantilli.com/linux-kernel-module-cheat#pagemap-dump-out
+ *
+ * This file is dual licensed as both 3-Clause BSD and GPLv3.
+ */
 
 #define _XOPEN_SOURCE 700
 #include <assert.h>
diff --git a/userland/linux/virt_to_phys_user.c b/userland/linux/virt_to_phys_user.c
index a891fb9..91950ad 100644
--- a/userland/linux/virt_to_phys_user.c
+++ b/userland/linux/virt_to_phys_user.c
@@ -1,4 +1,7 @@
-/* https://cirosantilli.com/linux-kernel-module-cheat#userland-physical-address-experiments */
+/* https://cirosantilli.com/linux-kernel-module-cheat#userland-physical-address-experiments
+ *
+ * This file is dual licensed as both 3-Clause BSD and GPLv3.
+ */
 
 #define _XOPEN_SOURCE 700
 #include <stdio.h> /* printf */
diff --git a/userland/posix/virt_to_phys_test.c b/userland/posix/virt_to_phys_test.c
index 9fbac93..c369d3a 100644
--- a/userland/posix/virt_to_phys_test.c
+++ b/userland/posix/virt_to_phys_test.c
@@ -1,4 +1,7 @@
-/* https://cirosantilli.com/linux-kernel-module-cheat#userland-physical-address-experiments */
+/* https://cirosantilli.com/linux-kernel-module-cheat#userland-physical-address-experiments
+ *
+ * This file is dual licensed as both 3-Clause BSD and GPLv3.
+ */
 
 #define _XOPEN_SOURCE 700
 #include <stdint.h>