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                         <strong>Safety Warning - Used Lithium Cells</strong>
                         <ul>
                             <li>Used cells may have hidden defects not detectable by capacity/IR testing</li>
-                            <li>Internal resistance mismatch >20% can reduce cycle life by up to 40%
-                                <a href="https://doi.org/10.1016/j.jpowsour.2013.11.064" target="_blank"
-                                    rel="noopener">(Shi et al., 2013)</a>
-                            </li>
+                            <li>Internal resistance mismatch >20% can reduce cycle life by up to 40%</li>
                             <li>Always use a BMS with cell-level monitoring and balancing</li>
                             <li>Use only same model of cells in a pack.</li>
                             <li>Never charge unattended; use fireproof storage</li>