Extraction of the Mayer wave component in blood pressure from the instantaneous phase difference between electrocardiograms and photoplethysmograms. - Norihiro Sugita; Makoto Yoshizawa; Masayuki Murakoshi; Makoto Abe; Noriyasu Homma; Tomoyuki Yambe; Shin-ichi Nitta (Artif. Life Robotics, 2010)