diff --git a/armsrc/umm_info.c b/armsrc/umm_info.c
index 42a22c415..93fe375e5 100644
--- a/armsrc/umm_info.c
+++ b/armsrc/umm_info.c
@@ -7,6 +7,7 @@
 #ifdef UMM_INFO
 
 /* ----------------------------------------------------------------------------
+ * From https://github.com/rhempel/umm_malloc
  * One of the coolest things about this little library is that it's VERY
  * easy to get debug information about the memory heap by simply iterating
  * through all of the memory blocks.
diff --git a/armsrc/umm_integrity.c b/armsrc/umm_integrity.c
index c998efcf9..b5a115bf0 100644
--- a/armsrc/umm_integrity.c
+++ b/armsrc/umm_integrity.c
@@ -5,6 +5,7 @@
 
 #ifdef UMM_INTEGRITY_CHECK
 /*
+ * From https://github.com/rhempel/umm_malloc
  * Perform integrity check of the whole heap data. Returns 1 in case of
  * success, 0 otherwise.
  *
diff --git a/armsrc/umm_malloc.c b/armsrc/umm_malloc.c
index a8c17609c..44573f75d 100644
--- a/armsrc/umm_malloc.c
+++ b/armsrc/umm_malloc.c
@@ -1,6 +1,7 @@
 /* ----------------------------------------------------------------------------
  * umm_malloc.c - a memory allocator for embedded systems (microcontrollers)
  *
+ * From https://github.com/rhempel/umm_malloc
  * See LICENSE for copyright notice
  * See README.md for acknowledgements and description of internals
  * ----------------------------------------------------------------------------
diff --git a/armsrc/umm_malloc.h b/armsrc/umm_malloc.h
index 171abcfb9..959201f4d 100644
--- a/armsrc/umm_malloc.h
+++ b/armsrc/umm_malloc.h
@@ -1,6 +1,7 @@
 /* ----------------------------------------------------------------------------
  * umm_malloc.h - a memory allocator for embedded systems (microcontrollers)
  *
+ * From https://github.com/rhempel/umm_malloc
  * See copyright notice in LICENSE.TXT
  * ----------------------------------------------------------------------------
  */
diff --git a/armsrc/umm_poison.c b/armsrc/umm_poison.c
index c2fd6a899..003a6a988 100644
--- a/armsrc/umm_poison.c
+++ b/armsrc/umm_poison.c
@@ -1,4 +1,5 @@
 /* poisoning (UMM_POISON_CHECK) {{{ */
+/* From https://github.com/rhempel/umm_malloc */
 
 #include <stdint.h>
 #include <stddef.h>