Update app.py

app.py

@@ -223,8 +223,8 @@ async def websocket_endpoint(websocket: WebSocket):
                             if (index+1) in citation_numbers:
                                 sources[f"[{index+1}]"] = doc.metadata["source"]
                             else:
-                                if i <= 5:
-                                    backup[str(i)] = doc.metadata["source"]
+                                if doc.metadata["source"] not in backup.values():
+                                    backup[f"[{i}]"] = doc.metadata["source"]
                                     i += 1
                         if sources:
                             await websocket.send_json({'sources': sources})