@conference {1483, title = {Instantaneous estimation of high-order nonlinear heartbeat dynamics by Lyapunov exponents}, booktitle = {2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)}, year = {2012}, pages = {13{\textendash}16}, publisher = {IEEE}, organization = {IEEE}, keywords = {Bioengineering}, author = {L. Citi and G. Valenza and R. Barbieri} }