AUTHOR=Spasić Sladjana Z. , Kesić Srdjan TITLE=Editorial: Nonlinearity in Living Systems: Theoretical and Practical Perspectives on Metrics of Physiological Signal Complexity JOURNAL=Frontiers in Physiology VOLUME=10 YEAR=2019 URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2019.00298 DOI=10.3389/fphys.2019.00298 ISSN=1664-042X