diff --git a/content_extraction.py b/content_extraction.py
index a4551594d77903825cc77f190488dda6150fa6ba..afd0aaef65cb05d1b1d54585a4dc21d4991235a2 100644
--- a/content_extraction.py
+++ b/content_extraction.py
@@ -1,3 +1,5 @@
+# Reference: https://platform.openai.com/docs/guides/vision
+
 import subprocess
 import sys
 import os