Contact‐Free Screening of Atrial Fibrillation by a Smartphone Using Facial Pulsatile Photoplethysmographic Signals oleh Bryan P. Yan, William H. S. Lai, Christy K. Y. Chan, Stephen Chun‐Hin Chan, Lok‐Hei Chan, Ka‐Ming Lam, Ho‐Wang Lau, Chak‐Ming Ng, Lok‐Yin Tai, Kin‐Wai Yip, Olivia T. L. To, Ben Freedman, Yukkee C. Poh, Ming‐Zher Poh