Added references

lod/01_SPARQL_Introduction.ipynb

@@ -1727,7 +1727,9 @@
     "GROUP_CONCAT(?name; separator=\",\")\n",
     "```\n",
     "\n",
-    "Using `GROUP_CONCAT`, get a list of the instruments that each musician could play."
+    "Using `GROUP_CONCAT`, get a list of the instruments that each musician could play.\n",
+    "\n",
+    "You can consult how to use GROUP_CONCAT [here](https://www.w3.org/TR/sparql11-query/)."
    ]
   },
   {
@@ -1769,7 +1771,9 @@
     "In one of the exercises, we excluded lead and backing vocals from the list of instruments.\n",
     "However, are those the only types of vocals?\n",
     "\n",
-    "You can check if a string or URI matches a regular expression with `regex(?variable, \"<regex>\")`."
+    "You can check if a string or URI matches a regular expression with `regex(?variable, \"<regex>\", \"i\")`.\n",
+    "\n",
+    "Consult if needed how to use regular expressions with SPARQL [here](https://www.w3.org/TR/rdf-sparql-query/)."
    ]
   },
   {
@@ -1840,7 +1844,24 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.7.2"
+   "version": "3.5.5"
+  },
+  "latex_envs": {
+   "LaTeX_envs_menu_present": true,
+   "autocomplete": true,
+   "bibliofile": "biblio.bib",
+   "cite_by": "apalike",
+   "current_citInitial": 1,
+   "eqLabelWithNumbers": true,
+   "eqNumInitial": 1,
+   "hotkeys": {
+    "equation": "Ctrl-E",
+    "itemize": "Ctrl-I"
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