diff --git a/sorting-searching/insertion-sort.ipynb b/sorting-searching/insertion-sort.ipynb
index 6b822a6..d93a6fc 100644
--- a/sorting-searching/insertion-sort.ipynb
+++ b/sorting-searching/insertion-sort.ipynb
@@ -1,5 +1,12 @@
 {
  "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<small><i>This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://bit.ly/code-notes).</i></small>"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -120,7 +127,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython2",
-   "version": "2.7.9"
+   "version": "2.7.10"
   }
  },
  "nbformat": 4,
diff --git a/sorting-searching/merge-sort.ipynb b/sorting-searching/merge-sort.ipynb
index b87d6e2..1b406d8 100644
--- a/sorting-searching/merge-sort.ipynb
+++ b/sorting-searching/merge-sort.ipynb
@@ -1,5 +1,12 @@
 {
  "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<small><i>This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://bit.ly/code-notes).</i></small>"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -140,7 +147,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython2",
-   "version": "2.7.9"
+   "version": "2.7.10"
   }
  },
  "nbformat": 4,
diff --git a/sorting-searching/quick-sort.ipynb b/sorting-searching/quick-sort.ipynb
index 34d5e64..5103da9 100644
--- a/sorting-searching/quick-sort.ipynb
+++ b/sorting-searching/quick-sort.ipynb
@@ -1,5 +1,12 @@
 {
  "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<small><i>This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://bit.ly/code-notes).</i></small>"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -151,7 +158,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython2",
-   "version": "2.7.9"
+   "version": "2.7.10"
   }
  },
  "nbformat": 4,
diff --git a/sorting-searching/selection-sort.ipynb b/sorting-searching/selection-sort.ipynb
index 2099aeb..5bf6ccb 100644
--- a/sorting-searching/selection-sort.ipynb
+++ b/sorting-searching/selection-sort.ipynb
@@ -1,5 +1,12 @@
 {
  "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<small><i>This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://bit.ly/code-notes).</i></small>"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -140,7 +147,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython2",
-   "version": "2.7.9"
+   "version": "2.7.10"
   }
  },
  "nbformat": 4,