diff --git a/docs/std_cdisc.ipynb b/docs/std_cdisc.ipynb
index 765bea0c..2d3cc000 100644
--- a/docs/std_cdisc.ipynb
+++ b/docs/std_cdisc.ipynb
@@ -130,7 +130,7 @@
             "source": [
                 "### Get CT Packages\n",
                 "\n",
-                "CDISC Controlled Terminology (CT) is maintained and distributed as part of the National Cancer Institute (NCI) Thesaurus.\n",
+                "CDISC Controlled Terminology (CT) is maintained and distributed as part of the National Cancer Institute (NCI) Thesaurus [^5].\n",
                 "\n",
                 "\n",
                 "To get a list of newest CT packages available:\n",
@@ -162,7 +162,7 @@
                 "- MRCT: multi-regional clinical trials\n",
                 "- COA: clinical outcome assessment. This is an archived version. COA is part of QRS supplement supporting FDA COA qualification program [^6].\n",
                 "- QRS: questionnaires, ratings and scales. This is an archived version. QRS SDTM CT is currently included in SDTM CT. \n",
-                "- QS-FT: questionnaire and functional test. This is an archived version. This set was merged into COA at 2014 [^r7]."
+                "- QS-FT: questionnaire and functional test. This is an archived version. This set was merged into COA at 2014 [^7]."
             ]
         },
         {