diff --git a/src/Text/Pandoc/Readers/Markdown.hs b/src/Text/Pandoc/Readers/Markdown.hs
index d7e59c7fd..1bcf1cfae 100644
--- a/src/Text/Pandoc/Readers/Markdown.hs
+++ b/src/Text/Pandoc/Readers/Markdown.hs
@@ -1695,8 +1695,10 @@ endline = try $ do
 
 -- a reference label for a link
 reference :: PandocMonad m => MarkdownParser m (F Inlines, String)
-reference = do notFollowedBy' (string "[^")   -- footnote reference
-               withRaw $ trimInlinesF <$> inlinesInBalancedBrackets
+reference = do
+  guardDisabled Ext_footnotes <|> notFollowedBy' (string "[^")
+  guardDisabled Ext_citations <|> notFollowedBy' (string "[@")
+  withRaw $ trimInlinesF <$> inlinesInBalancedBrackets
 
 parenthesizedChars :: PandocMonad m => MarkdownParser m [Char]
 parenthesizedChars = do
diff --git a/test/command/3840.md b/test/command/3840.md
new file mode 100644
index 000000000..ceb1d1e51
--- /dev/null
+++ b/test/command/3840.md
@@ -0,0 +1,15 @@
+```
+% pandoc
+[@Alhazen1572-qk, V.9]: "competentius est"
+^D
+<p><span class="citation" data-cites="Alhazen1572-qk">[@Alhazen1572-qk, V.9]</span>: “competentius est”</p>
+```
+
+```
+% pandoc -f markdown-citations
+[@Alhazen1572-qk, V.9]: "competentius est"
+
+[@Alhazen1572-qk, V.9]
+^D
+<p><a href="" title="competentius est">@Alhazen1572-qk, V.9</a></p>
+```