diff --git a/serve.py b/serve.py
index e131ef7..7fb278e 100755
--- a/serve.py
+++ b/serve.py
@@ -321,8 +321,9 @@ def main():
     argparser = argparse.ArgumentParser(description='Server for online tests. Enrolled students and tests have to be previously configured. Please read the documentation included with this software before running the server.')
     argparser.add_argument('testfile', type=str, nargs='+', help='test/exam in YAML format.') # FIXME only one exam supported at the moment
     argparser.add_argument('--allow-all', action='store_true', help='Students are initially allowed to login (can be denied later)')
-    argparser.add_argument('--debug', action='store_true',
-        help='Enable debug messages.')
+    argparser.add_argument('--debug', action='store_true', help='Enable debug messages')
+    argparser.add_argument('--show-ref', action='store_true', help='Show question references')
+
     arg = argparser.parse_args()
 
     # --- Setup logging
@@ -342,6 +343,7 @@ def main():
         'filename': arg.testfile[0] or '',
         'debug': arg.debug,
         'allow_all': arg.allow_all,
+        'show_ref': arg.show_ref,
     }
 
     try:
diff --git a/templates/question.html b/templates/question.html
index ba726ad..2e34215 100644
--- a/templates/question.html
+++ b/templates/question.html
@@ -22,5 +22,11 @@
       </small>
     </p>
   </div>
+  
+  {% if show_ref %}
+    <div class="card-footer">
+      <code>{{ q['ref'] }}</code>
+    </div>
+  {% end %}
 </div>
 {% end %}
\ No newline at end of file
diff --git a/templates/review-question.html b/templates/review-question.html
index 79baffb..f43dbd5 100644
--- a/templates/review-question.html
+++ b/templates/review-question.html
@@ -50,6 +50,11 @@
             {{ q['comments'] }}
           </p>
         {% end %}
+
+        {% if t['show_ref'] %}
+          <code>{{q['ref']}}</code>
+        {% end %}
+        
       </div> <!-- card-footer -->
     </div> <!-- card -->
 
@@ -77,13 +82,17 @@
           </small>
         </p>
       </div> <!-- card-body -->
-
       <div class="card-footer">
         <p class="text-secondary">
           <i class="fa fa-ban fa-3x" aria-hidden="true"></i>
           {{ round(q['grade'] * q['points'], 2) }} pontos<br>
           {{ q['comments'] }}
         </p>
+
+        {% if t['show_ref'] %}
+          <code>{{ q['ref'] }}</code>
+        {% end %}
+
       </div> <!-- card-footer -->
     </div> <!-- card -->
   {% end %} <!-- if answer not None -->
diff --git a/templates/test.html b/templates/test.html
index d4d8c46..ace82d7 100644
--- a/templates/test.html
+++ b/templates/test.html
@@ -84,7 +84,7 @@
 
   <form action="/test" method="post" id="test" autocomplete="off">
     {% for i, q in enumerate(t['questions']) %}
-      {% module Template(templ[q['type']], i=i, q=q, md=md) %}
+      {% module Template(templ[q['type']], i=i, q=q, md=md, show_ref=t['show_ref']) %}
     {% end %}
 
     <div class="form-row">
--
libgit2 0.21.2