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index f2ea71b..d25f874 100644
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@@ -12,7 +12,7 @@
 <div class="module-sub-item p-3">
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         <div class="col-9"><span class="theme-text-secondary mr-2">9.2</span>A
-            <a href="https://www.guru99.com/java-interface.html" class="reference-link">source</a>
+            <a href="https://www.javatpoint.com/interface-in-java" class="reference-link">source</a>
             with good explanation on the subject
         </div>
         <div class="col-3 text-right extra-info"><span class="icon dripicons-download mr-2"></span>Documentation