<span class="citations"><p>Angelo Signor, Alfredo Guerrato, Giovanni Signor, "Process for the preparation of furosemide." U.S. Patent US5739361, issued June, 1971.</p>
</span><a href="https://www.google.com/?tbm=pts#q=5739361&amp;tbm=pts" rel="noopener" target="_blank">US5739361</a>