Fausto Lucena Allan Kardec Barros Yoshinori Takeuchi Noboru Ohnishi Heart Instantaneous Frequency Based Estimation of HRV from Blood Pressure Waveforms. 529-537 2009 92-D IEICE Transactions 3 http://search.ieice.org/bin/summary.php?id=e92-d_3_529&category=D&year=2009&lang=E&abst= db/journals/ieicet/ieicet92d.html#LucenaBTO09