add ipyaladin citation instructions

notebooks/multi_mission/display_footprints/display_footprints.ipynb

@@ -396,13 +396,21 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## About this Notebook\n",
+    "## Citations\n",
+    "If you use ipyaladin for your work or research, you should cite it with the following acknowledgment:\n",
+    "\n",
+    "This research made use of ipyaladin, developed by CDS, Strasbourg Astronomical Observatory, France (DOI: [10.26093/kpaw-kb74](https://doi.org/10.26093/kpaw-kb74)).\n",
+    "\n",
+    "[2020ASPC..522..117B](https://ui.adsabs.harvard.edu/abs/2020ASPC..522..117B) - ipyaladin: Enabling Aladin Lite in Jupyter Notebooks (Boch T. et al.)\n",
     "\n",
+    "\n",
+    "## About this Notebook\n",
     "If you have comments or questions on this notebook, please contact us through the Archive Help Desk e-mail at [email protected].\n",
     "\n",
+    "\n",
     "**Authors:** Brian McLean, Thomas Dutkiewicz <br>\n",
     "**Keywords:** Footprints <br>\n",
-    "**Last Updated:** June 2024 <br>\n",
+    "**Last Updated:** Aug 2024 <br>\n",
     "\n",
     "***\n",
     "[Top of Page](#top)\n",
@@ -426,7 +434,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.12.1"
+   "version": "3.12.4"
   }
  },
  "nbformat": 4,